I love the shaking hands to discretely tip story. I wish I had a story like that but I have the opposite - a failure to tip. I was trying to tip the bartender at the conference dinner last week where they only accepted payment using cards but they could not accept tips via card - only cash. Because we had all been notified in advance that payment was cashless, I had no cash with me at all and I was frustrated that there was no way I could tip. I think people may use Venmo in these circumstances but I don't have a Venmo. I guess I need to set one up.