"Here's another little tid bit....If you pay with a credit card, and it list a place to add a tip...don't...If you're going to tip, give it directly to the person who served you..." Extremely good point. That is the only way to guarantee that the tip actually gets into the pocket of the person to whom you intend it to go. Cash in their hand is the way to go! It completely eliminates any "middle man."
I am on the road 30+ weeks a year and my employer picks up expenses including tips. In MT 90% of the time when they see a tip on the CC receipt they pull it out of the till and set it aside.