Such an outcome threatens to offset any extra rewards you accrued.

44 percent say they weren't paid back on at least one occasion.

Nearly 30 percent of young adults offer to pick up the tab because they're in pursuit of credit card miles and perks, according to a survey from CreditCards.com.

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The dinner check arrives and, what do you know? Some people have to use the restroom. Meanwhile, others pick up the bill with a grin. They, too, may be scheming. Nearly 30 percent of young people offer to pick up the tab because they're in pursuit of credit card miles and perks, according to a new survey from CreditCards.com, which interviewed 1,005 adults in the beginning of May. Some 13 percent of baby boomers do the same. "Those moves are how people really ramp up their rewards," said Matt Schulz, senior industry analyst at CreditCards.com.

Reward points are just a fraction of what you spend. Kimberly Palmer credit card expert at personal finance website NerdWallet

Maneuvering your way into extra points is not as simple as it may sound, however. Usually, these point collectors expect to be reimbursed by their friends or family members, but that outcome doesn't always arrive. Indeed, 44 percent of people who take on the check say they weren't paid back on at least one occasion, CreditCards.com found. This threatens to offset any extra rewards you accrued. "Reward points are just a fraction of what you spend," said Kimberly Palmer, credit card expert at personal finance website NerdWallet. More from Personal Finance:

To knock out debt, reassess your payoff plan

4 steps to help you get debt free

Credit card debt hits record high Here's how to best navigate your way to extra points.

Assess if the risk is worth the reward

Since there could be a chance you won't be reimbursed when you pick up other people's costs, you'll want to factor in the worst-case scenario in deciding if you should take them on in the first place, Schulz said. "Would you be okay picking up a $200 restaurant bill if ultimately no one paid you back?" he asked.

You also want to consider who you're temporarily treating. Are you out with people you've known for years and who've paid you back before? Or is this your first time out with this group? That answer can help you decide if it's worth it.

Be upfront

"The best case scenario is you plan ahead for these situations so you're not chasing after your friends later," said Miriam Kirmayer, a therapist and friendship researcher. Ask your friends in advance if it would be okay if you paid the bill, and establish how they're going to reimburse you. If you haven't had the discussion beforehand, "collect cash from your friends on the spot, or have them send the money to you while everyone is still sitting at the table by using a money transfer service such as Venmo or PayPal," said Julian Kheel, senior editor at The Points Guy, a website that refers credit cards to consumers. Make your intentions clear, for you're surely not the only point collector. "If you're out with a group of people who all play the rewards game, you might get some pushback," Schulz said. "Be prepared for someone to say, 'No'."

If you haven't been paid back