The Justice Department, which prosecutes tax evasion cases, is making sure people know that the penalties are real. Earlier this month, it announced that a California man named Robert E. Greeley had pleaded guilty to filing a false income tax return that concealed $13 million in two offshore accounts at UBS in Switzerland. Mr. Greeley paid a $6.8 million penalty for his failure to file a report of foreign bank accounts.

The penalty could have been worse. Mr. Greeley had set up two shell companies in the Cayman Islands to hide his ownership of the accounts. When someone willfully seeks to evade taxes, as he did, the penalty can be as high as 50 percent of the account value for every year it existed. (A separate fraud penalty can also be levied.)

“Some people will say, ‘I didn’t have my account at UBS so they’re not going to find out,’ ” said Warren Whitaker, a partner in the individual clients department at Day Pitney in New York. “The reality is the world is shrinking, and people who think they can squeak by and they won’t get caught are kidding themselves.”

So regardless of how the rest of us may feel about tax evaders, what should someone with an offshore account do? There are two options: join the program or go it alone and take your chances. Here’s a look at the two options.

VOLUNTARY DISCLOSURE The main benefit of the second round of the I.R.S.’s offshore voluntary disclosure initiative is that people who come forward will not face criminal charges. They will owe a lot of penalties, but these may be less than if they were caught. (While the program officially ends on Sept. 9, the I.R.S. has said taxpayers who make a good-faith effort to comply may be able to file for an extension.) There are three groups of people for whom this program makes a lot of sense.