By now, you're probably used to tipping by tablet. You know -- when it comes time to pay a bill and you swipe your card into a tablet to settle up. And then a range of suggested tips are presented.
The payment apps say it's all about customer convenience, but here's "a tip:" Research shows the defaults are leading many to dole out more dollars.
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High-tech tipping, where tips are suggested for you on a digital payment system, are common everywhere from restaurants to hair salons, taxi cabs to coffee shops.
"You might be prompted for a tip in places that you don't expect. So you might be prompted for a tip at your local bakery or at your local food truck," NerdWallet's Liz Weston said.
[RELATED: How much should you be tipping for services? | Q&A: What's the proper tipping etiquette?]
She determined the digital checkouts are not only adding tips where tips didn't exist before, but that the size of the suggestions are creeping up, too.
And that's not all.
"Sometimes, a tipping option might be prechecked for you. This is something my editor ran into when he went to get a haircut. That's where he saw the 25 percent tip as the suggested tip," Weston said.
Some apps preprogram suggestions up to 25 percent. Others allow businesses to set the tips at whatever amount they want.
Many times, you can click a "no tip" button, but one report finds nearly a third of those asked said the button would actually increase their chances of leaving a tip.
Research also shows whenever people are offered a range, they tend to go for the middle option.
Experts said with a normal tip possibly being around 15 percent, they might be trying to get it up to 25 percent, and maybe they just hope you'll settle for 20 percent.
Websites of some leading payment systems tout customer convenience, saying that the programs "calculate the math" and offer "digital receipts," but, he "suggested tip options keep employees happy, too."
"This is a trend that's going to grow because the merchants have discovered it does boost tips," Weston said.
Weston said no matter what the buttons say, remember: You are always in control.
"Take a breath and make sure you're tipping the amount that you want to tip. If you can't find the custom option, then don't leave any tip at all via the app and give the person something in cash," Weston said.
The Small Business Administration was asked for a comment to provide as reaction from the small business side, but has not responded.
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Also, it's worth noting that while the suggestions have gone up, tipping rules haven't changed.
The etiquette is still 15-20 percent for good service at a sit-down restaurant, 10-15 percent for home delivery and 15-20 percent for a taxi.
Click here for a full tipping guide.