Royal Caribbean is telling us that passports are needed for a cruise to Ensenada, Mexico, but I've been reading the papers and I know that's not true. Passports are so expensive. Can you look into this?

You are correct: U.S. citizens won't need a passport to cruise or drive into Mexico or Canada until June 1, 2009. On the other hand, we don't want to see you and your family left on the dock in San Pedro this summer while an overzealous Royal Caribbean sails off without you.

So we checked with headquarters. Harrison Liu, a spokesman for the cruise line, says: "Royal Caribbean at this time is advising our guests to have a passport in order to travel to the Mexican Riviera and on our short cruises sailing from Los Angeles." He said that means they are asking for but not requiring a passport.

Can he guarantee you won't have a problem boarding without a passport?

"Yes. We haven't had any problem with the authorities in the ports," Liu said.

As for Royal Caribbean's strong encouragement for passports, Liu makes a good point: If someone in your party has a medical problem or personal emergency and needs to fly home quickly, well, that's when you're going to wish you had a passport.

For the record, Bill Knight, owner of All Cruise Travel in San Jose, puts a lot of clients on cruise ships to Mexico and has heard no complaints from the nonpassport-holders among them. However, he said, "There certainly will be a problem if they don't bring proof of citizenship."

You can be denied boarding if you don't have a birth certificate and a government-issued photo ID, such as a driver's license.

For more details, go to travel.state.gov.