A high school band in Washington state has canceled a longstanding field trip to Canada over concerns that some of its students may be barred from re-entering the United States.

For 18 years, the school band from Kentlake high school has crossed the border to take part in the Victoria Day parade in British Columbia. The Seattle-based school board decided last week to cancel the trip in order to protect students who may be undocumented, said Chris Loftis, a district spokesperson.

“You can’t go on a field trip with 100 kids and come back with 99,” Loftis told the Canadian Broadcasting Corporation.

Reaction to the decision has been mixed, he said. “There’s some folks who feel that this is overreacting. There’s some folks who say no, this is a civil rights issue. Others say no, this is an overreaction to some confusing language from the White House and this will all blow over.”

Earlier this year, amid concerns over the White House’s attempts to impose a travel ban and heightened anxiety among students affected by immigration issues, a school board official called US Customs and Border Protection to clarify what Loftis described as the “sometimes confusing messaging” emerging from Donald Trump’s administration.

The board – which ranks among the most diverse in the US, with students who hail from more than 100 countries and speak more than 135 languages – was told that any student lacking adequate documentation of legal US residency would have a very high chance of being detained at the border, Loftis told the Seattle Times.

The response was to cancel all international field trips, including the band trip to Victoria and a forthcoming exchange trip to Osaka, Japan. The decision was not taken lightly, said Karen DeBruler, the school board president, given the months of planning and fundraising that went into the trips.

“But things are changing on a very unprecedented basis,” she said. And allowing some students to go would mean that those held back would be “exposed as being undocumented”, she added.

Across the border, the organisation handling the registration for the Victoria Day parade noted that several other high school bands from Washington and Oregon are still planning to attend. A group from the University of Washington is also expected to join in the festivities.

In a statement, US Customs and Border Protection noted that there had been no change in immigration laws: “In accordance with the Immigration and Nationality Act, all travellers seeking to enter the United States must prove to the inspecting officer that they are legally entitled to enter the United States.”