One of the montly golf publications actually did an informal survey of a few Tour players a month or so ago, and published random results. The curiosity I guess comes from the fact that Tour players probably have to do a lot of tipping at every tournament, to acknowledge those that help them in and around the clubhouse, along with the occasional money card/dice game, etc. The results that were published were rather interesting, ranging from one Tour employee who carried ZERO cash (used a debit card for everything), to Phil Michelson, whose reputation for dropping MAJOR tips on waitresses, et al, is legendary (A $20 tip for two hot dogs, a $100 tip for serving him dinner at a restaurant). The article did tell us at the end that Mickelson carried on him (at that time) $8,100 in cash. Some in hundreds and some in 20's.
The other interesting one was Zach Johnson and his caddie. Turns out that Zach carries less than his caddie, as I guess his caddie is always involved in some sort of card game, and carries about $800 on him at all times. (The numbers may be escaping me, so I apologize for any inaccuracies for those who read the article.
All that said, it is a curious question to ask, and obviously you don't have to participate if you don't want to. And because I brought it up, I'll disclose...
I generally pay most everything with a debit card, and usually have less than $40 in cash on me. Not much of a need to tip in cash anymore, as most restaurants take plastic, but I do like to pay my barber in cash ($15 for the cut and a $5 tip).
The thread is open, have fun.