(CNN) A civil rights watchdog on Tuesday issued a "travel alert" for Texas, saying a law targeting sanctuary cities threatens to turn Texas into a "show me your papers state" and could expose travelers to rights violations and illegal arrests.

The alert is not just for Texans, the American Civil Liberties Union says. It's for anyone traveling through the Lone Star State. Eighteen state ACLU affiliates have issued alerts for its residents traveling though Texas.

At least one organization representing Texas police says it's "fearful" of what the law could mean for rank-and-file officers.

Governments who violate the law can be fined up to $25,500 a day; sheriffs and police chiefs can be charged with misdemeanors for refusing to comply with federal detainer requests; elected and appointed officials can be removed from office for violations of the law.

"There are deadly consequences to not enforcing the law, and Texas has now become a state where those practices are not tolerated. With this bill we are doing away with those that seek to promote lawlessness in Texas," the governor said in a news release.

Draconian or overpoliticized?

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The ACLU painted the bill quite differently, saying SB4 "gives a green light to police officers in the state to investigate a person's immigration status during a routine traffic stop, leading to widespread racial profiling, baseless scrutiny, and illegal arrests of citizens and non-citizens alike presumed to be 'foreign' based on how they look or sound."

"Texas is a state with deep Mexican roots and home to immigrants from all walks of life. Many of us fit the racial profile that the police in Texas will use to enforce Trump's draconian deportation force," Lorella Praeli, ACLU director of immigration policy and campaigns, said in a statement.

Kevin Lawrence, executive director of the Texas Municipal Police Association, says the debate over sanctuary cities has been overpoliticized on both ends, and while SB4 provides the state's police with a needed resource, it does not mean officers will be pulling over people for driving while brown.

"Law enforcement needs to be able to service the communities we serve, whether they're legal or not. We don't want them scared," he said. "It's not good police work for us to go out checking everyone's immigration status all day, every day. We do when we need to, but not as a matter of course."

The TMPA supports the law, he said, because it prohibits city councils and county commissions from passing local laws that prohibit policemen for enforcing the law or "threaten (officers') jobs if they do their jobs."

Such was the case in February when a Travis County law went into effect restricting law enforcement from cooperating with federal immigration officials, prompting Abbott to deny the county $1.5 million in grants. Travis County is the only jurisdiction in the state with such a law.

"It should be obvious that my implementation of a policy, meant to meet our community's need, did not violate any law. Otherwise, the Texas Legislature wouldn't have felt compelled to make a new one," Travis County Sheriff Sally Hernandez said this weekend in denouncing SB4. "I am disappointed, because this is not in the best interest of public safety. It ties the hands of our law enforcement agency and pushes victims of crime into the shadows."

More fights, police chases?

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Charley Wilkison, executive director of the Combined Law Enforcement Associations of Texas, said his organization had no stance on SB4 until the state House added an amendment requiring officers to inquire about immigration status. Under current law, officers saved this question until after they had made an arrest; starting in September, they'll have to do it during routine traffic stops.

Wilkison feels complaints are "going to roll in" as officers make quick decisions on whom to ask and whom not to ask about their immigration status.

"We feel like that exposes the officer to massive amounts of complaints. We think it exposes them legally. We think it exposes them to some safety issues," Wilkison said, explaining his organization stands "in extreme opposition to the bill."

Like Lawrence, he believes the debate over sanctuary cities is heavily politicized. Texas legislators sacrificed officers' well-being in order to score political points, Wilkison said.

The law takes away one of the most important tools in policing -- an officer's discretion -- without providing a cent for additional training, he said. When officers pull someone over or respond to an address, they tend to survey the situation and make sure everyone's safe before determining whether crimes were committed. That's out the window, Wilkison said, as officers now will have to make immigration status a priority.

"The onus of the immigration debate is balanced on the back of working cops," he said.

The first two minutes of a traffic stop are the "riskiest and deadliest for both sides. They're both very vulnerable to a misunderstanding or fear, all sorts of things," Wilkison said.

Add to this the possibility that drivers could be separated from their homes, spouses, children and livelihoods if they give the wrong answer to an officer's question about immigration status, and it's evident how quickly things can go awry, Wilkison said.

"I believe they'll run or fight," he said.

'Racist and wrongheaded'

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Lawrence, who served on the Texas police forces in Baytown, Georgetown and Seabrook during his 22-year career, contends the law does not mandate that local law enforcement cooperate "regarding all things immigration."

He also notes that the law specifically prohibits considering "race, color, religion, language, or national origin while enforcing immigration laws."

As a law enforcement tool, it would allow a police officer to check someone's immigration status if they were being detained on suspicion of criminal activity -- suspicion being a lower bar than the probable cause required for an arrest, Lawrence said.

As an example, he said, an officer might detain a driver who is weaving on suspicion of driving under the influence. The officer would continue detaining the driver -- observing the driver, talking to her or him, perhaps conducting sobriety tests -- until the officer was satisfied the driver was sober or the officer had probable cause for a DUI arrest. It's only during detention or arrest that police can check immigration statuses under SB4, he said.

Terri Burke, the ACLU of Texas' executive director, has called SB4 "racist and wrongheaded." According to ACLU data, US Immigration and Customs Enforcement between 2008 and 2012 requested local law enforcement hold 834 US citizens, "even when they lack the legal authority to do so." Some of those Americans spent days in jail, in what the watchdog organization called "the federal government's constitutionally flawed use of detainer requests."

"It is simply a matter of time before illegal arrests occur. Local law enforcement will have to decide between violating a person's rights and being severely fined, thrown in jail, or even being removed from office for choosing not to do so," said Burke.

But Lawrence believes the specter of rights violations and illegal arrests is overblown, and a misinterpretation of the law. Officers simply don't have time to begin stopping Texas drivers solely to check their immigration statuses, he said.

"We've got a lot more important things to do," he said.