According to the company, Square users saw a 35% increase in tip frequency in 2014 from 2013. The average tip is around 17%. "As far as tipping, ...

Eight months ago, when the shop switched to Square, tips shot up "a hefty amount," Luke said. Rather than being relegated to the bottom of a receipt, the tip is "just in your face," she said.

Merchants who use Square include a “No Tip” option. But it’s hard, for me at least, and I suspect others, to look at the barista holding the tablet and cough up nothing.