A passport snafu has cost a family their long-planned, two-week vacation on the French Riviera and thousands of dollars in extra flight costs.

Annie Dagenais and Tom Wurster say if you're not careful, it could easily happen to you.

"We've talked to a few people and seen some other stories," Wurster told CBC News. "This isn't an uncommon situation."

It's a situation experts say many travellers aren't aware of, but should be.

Dagenais and Wurster booked a two-week trip to Nice, France, last January with a departure date in April.

It was a dream vacation and expensive for the Cambridge, Ont., couple. However, they had access to a condo they could rent at a reasonable rate and they paid for the flights using RBC Travel Reward points, which they had been accumulating for months.

They booked tickets for themselves and their two-year-old daughter, Olivia, on American Airlines but ended up on a flight operated by American partner British Airways from Toronto Pearson, with a stopover in London.

Trouble started in London

The trouble started at Heathrow as they were about to board their connecting flight.

"I was on my way down the ramp and [a British Airways employee] turned [me] around, kind of tapped me on the shoulder, asked for my passport and asked when I was returning," Wurster recalled.

"They said 'You can't board this flight, sir, your passport's expired.' We had a little bit of a discussion about what that meant because we had no idea."

In fact, Wurster's passport hadn't expired.

When a valid passport isn't valid

However, many countries have a rule that states a passport must be valid for a certain amount of time beyond the end of a visit to their country.

The rule is in place in order to ensure a visitor who unexpectedly needs to stay for a period longer than originally planned still has a valid passport to leave the country. Some countries require passports to be valid for at least six months beyond the end of a stay.

France requires passports to be valid for 90 days after the return date. Wurster's passport was due to expire in 78 days.

Dagenais's and their daughter Olivia's passports were good well beyond 90 days but she was not comfortable continuing the trip without Wurster.

Mere moments to decide

"We had one or two minutes to make a decision," Dagenais said.

"So many months of planning to [end up] going on my own with her [Olivia]? Or am I coming back with him? So I chose him."

To make matters worse, this happened on Easter Weekend. They say the consulate told them it could be five days before a new passport would be ready.

Faced with the expense of staying in London, the family decided to return home. The return tickets — on short notice, on a holiday weekend — cost them almost $4,000.

Add to that the value of the original airfare and a night in a London hotel and the family figures they're out between $8,000 and $9,000. And of course, they also lost their dream vacation.

More common than you might think

"I'm surprised but not surprised. I think it's something that everyone who travels should be aware of, perhaps aren't aware of," said Simon Vaughan, senior editor of Outpost, Canada's largest adventure travel magazine.

It's not just the passport expiry date that can pose problems, Vaughan said.

"I've heard of people who were travelling to Africa on safari via the U.S. And they had an outstanding traffic violation in the U.S." Vaughan said.

"Wouldn't have been a problem in Kenya, South Africa, where ever they were going. But the U.S. wouldn't let them in. So even though they were only transiting through the U.S., there for an hour, they had to reorganize their trip. It cost them thousands of dollars to do it."

Who's to blame?

Airlines are considered liable by the arriving country if a passenger arrives with a passport that doesn't conform to that country's rules.

The carrier could face fines and is also responsible for returning the passenger immediately or as soon as possible and, if necessary, at the airline's expense.

So why then did British Airways allow Wurster to board its plane in Toronto only to pull him from the flight at Heathrow?

"The night before, you go online to get your seat and what do they ask you? Your passport number and the date that it expires," Dagenais said. "Why are you asking this if it's not relevant when you get to the airport? Stop us then."

In an email to CBC News, a spokesperson for British Airways said while it was not aware of the family's specific flight details, "BA.com states that customers need to ensure they have the right documents, such as passports and visas."

The spokesperson said it would have the airline's customer relations team review and respond to Wurster and Dagenais.

Technology trap?

Many airlines and airports use an automated system to check passport validity against a destination country's individual passport rules. British Airways and Heathrow airport both use a system called TravelDoc.

And unlike France with its 90-day rule, the U.K. requires only that passports be valid at least for the duration of the stay.

So Wurster's passport was valid for travel to London, but not to France.

Wurster and Dagenais feel British Airways shouldn't have charged them for the return flight from London.

"I'd be quite happy if British Airways stepped up to the plate and said 'You know sir, we really shouldn't have boarded you in Toronto, it cost you a lot of money.' If they could reimburse us for the money we're out [for the return ticket], then I think that's pretty reasonable," Wurster said.

"They ask for proper documents. We have proper documents," Dagenais added. "We had a valid passport. And to the day we came back, his passport was still valid for many weeks."

The next time, though, they're not taking any chances.

Wurster renewed his passport shortly after returning to Canada. It's good for 10 years. Well, actually nine and a half.

Do you know of a consumer issue? Contact Aaron Saltzman at aaron.saltzman@cbc.ca.