Cab drivers are the real ones getting scammed, unfortunately, and rarely have any way of recourse. When paying with card, they are rarely paid in a timely manner, if they get the proper amount at all. This is even before uber made medallions worthless. When I was growing up, it was a matter of common courtesy to use cash in situations like that, where you know the employer is going to play games with the employee when you pay with card, like a cabbie's fare or a waitress' tip. As we got older, most of us who worked in service industries & survived on tips knew this the hard way because we were also a victim of wage theft via skimming tips, etc.

I'm glad my city isn't allowing certain businesses to go completely cash free for this reason. The push to force credit card payments everywhere just hurts a class of people that are already vulnerable.