NEW YORK (MainStreet) — We've all seen the signs: "$40 charge for cards that spend the night" or "$20 overnight fee for tabs that aren't closed." But if you leave your credit card at a bar overnight, can the bar really charge a fee? Is it even legal? Could you dispute the charge? Here’s a look at what happens when you forget your card and what you can do to keep it safe.

Will you end up stuck with a fee?

Yes, it’s legal for bars to charge a fee, says Kevin Yuann, credit card director at NerdWallet.com.

“The fee they’re charging is essentially a convenience fee, like any other fee or surcharge that consumers pay every day,” he says. “There is a requirement that the consumer must be notified about that fee before it’s actually implemented, but if there is a prominently displayed sign at the bar, you’ve been put on warning.”

With that said, if there was no sign notifying you of this fee — or if it was too small or obscured for you to see — you do have the option of contesting the charge with your credit card company.

“If this policy is not prominently displayed, then I would dispute the charge,” says Odysseas Papadimitriou, founder and CEO of Evolution Finance and WalletHub.com. “You thought you were buying drinks, but now you find you were buying something else.”

If, when you show up to retrieve your card from the bar and they have already run your card without your permission, that’s definitely a point to challenge, as you did not authorize the transaction.

“If you didn’t sign to approve that transaction, that’s not legal. You do have rights around how your card is used,” Yuann says. “If you dispute the charge, then your credit card company would reach out to that merchant or that merchant’s bank to remediate the issue.”

It really depends on how badly you want to fight the charge, Yuann says. If the bar is totally inflexible about removing or waiving the charge and you genuinely don’t feel as if you were notified of the policy, it’s time to start the dispute process.

It’s always better to try to resolve things with the bar rather than escalate the situation, Yuann says. Although you may be upset at having to pay a fee, try to think of things from the bar’s standpoint.

“Your first instinct may be to say, ‘Well, it’s not like I intentionally left it,’ and there’s this sense that it’s unfair that they’re tacking on an additional fee when all they’re doing is holding on to your credit card. But there are challenges for the bar when that happens.”

Your card is a financial instrument, and when you leave your card behind, the bar feels as if they have financial responsibility for it, he says.

“They may have to lock your card up in the manager’s safe overnight, and then if the office hours of the restaurant are different from the opening hours of the restaurant, someone may have to schedule a specific time to meet with you and get your card back to you,” he says.

Also, because you haven’t signed for your bill, the bar is unable to close out your tab. It may be that tips for wait staff are unable to be tallied, and managers are unable to shut down for the night like usual.

“The establishment provided you some sort of good or service, but you’re basically not paying for it,” Yuann says.

Of course when you keep a tab open, there’s no disputing it’s a big convenience for the bar.

“When they don’t have to close out the check after each drink, people buy more, people drink more,” Papadimitriou says. “Bars that have these policies need to get their act together and realize these fees make no sense when in 99% of cases they’re the ones getting the convenience.”

What should you do if you forget your card at a bar?

Go back to the bar and get your card, or call to make sure it’s safe.

If you remember it in time, turn around and go get your card. If you don’t realize it until the next day or until you’re already a long way away, call and ask if they can put your card in a secure location until you can come back and get it, Yuann says.

Don’t cancel the card unless it’s absolutely necessary.

“I wouldn’t cancel it unless you know it’s really lost — if the bar confirms that they don’t have the card and you’ve exhausted looking in your pockets, purse or car,” Papadimitriou says. “Canceling a card can be a lot of hassle if you have recurring bills or subscriptions tied to your card.”

If you’re worried about the bar making a copy of your card, remember that you’re taking that chance every time the card leaves your side, he says.

“They could copy your card while you’re sitting at the bar if they wanted to. Once you’ve opened the tab, the damage is done. If the bar has your card, let them hang onto it until you can get back there. You’re not liable for fraudulent purchases,” he says.

Consider freezing new purchases.

If you can’t get back to retrieve your card in a timely manner, consider freezing new purchases, says Bethy Hardeman, consumer advocate for Credit Karma.

“Check with your card issuer, but you may be able to put a temporary block on purchases with your card while you work on getting it back,” she says, adding that it’s important to watch your account carefully for any activity.

Once you have your card back, let your credit card company know.

“They may release the hold, or they may choose to replace your card,” she says.

In the future, remember your card — or don’t leave it in the first place.

“If this has happened more than once, stop opening tabs,” Papadimitriou says. “Just pay for each drink. You’ll end up drinking less and spending less. Having tabs open is unhealthy for both your wallet and your body.”

By Kathryn Tuggle for MainStreet