There are lots of dos and don'ts when it comes to this. Here's a list one can use:
1. Tipping Tournament Directors applies to tournaments held in a bar or poolroom, not at Valley Forge, Las Vegas, etc.
2. Tipping should only be done when cash prizes are given, not for qualifiers or for cash prizes that are meant for qualifier purposes.
3. In tours, as opposed to single events, it is considered not just customary but good practice to tip. Those borderline rulings like walking in two minutes past the deadline might be overlooked if you've tipped recently. In single events, they simply fail to have enough frequency to create customs so tipping shouldn't even be anticipated.
4. Tipping is reserved to top finishers, not all cash finishers. Typically, first place should tip approximately 10%. Second place should also tip but can leave whatever they want. If a deal is made, the tip should be worked out in the deal.
5. Unlike a waiter in a restaurant, the Tournament Director does not work for tips. In fact, even though it may be considered customary, it is not necessary. If a player fails to tip, nothing should be said about it. The rule of thumb is, if they win often enough, they will eventually catch on.
However, even though I've typically tipped in the past, I'm not 100% certain what I would do in a scenario where the tour director was also a participant in the field (as is typically the case in Joss events and Predator events). If the tour director finished high in the event, my tip may be less. However, finishing in the finals of a Joss or Predator event isn't going to happen for me any time soon but I'll gladly ponder such a predicament when the situation presents itself.
I also do not know what would happen in a major professional event like the U.S. Open. I would venture to say tipping is not common.
