Curious what others do.
I always tip on my credit card receipt (for the added points), but was told recently cash is preferred, mainly because in some establishments, unscrupulous owners try to steal part of the tip from the wait staff when left on a credit card.
I think it has more to do with tax liability to be honest
Always remember to fill in the tip and total lines on the merchant receipt copy, even if you tip in cash. I have had the unfortunate experience of making that mistake and having a disonest server write in their own tip after I left them cash.
Once upon a time, I left tips on my card. That was before a waiter had the audacity to add a tip on my card after the worse service I'd ever had. Four years later, another waiter changed the amount of the tip I left on my card. Now I ALWAYS, ALWAYS tip in cash and mark through the tip line on the receipt. That's just my experience though.
+1 to the tax liability. Most restraunts only require the wait staff to report a percentage of their tips, not the amounts in entirety.
I always use cash and put cash in the tip line. Lessens the chance of them being dishonest.
I always tip in cash and pay with CC.