Well, not surprisingly, the answers varied. I am probably guilty of over-tipping, which seemed harmless... but I do think it becomes an expectation. Some of the guys may even over-estimate their value as a result.
I think I will pay attention to how many times they check their phone, and adjust downward accordingly. My favorite guys do not do this - but quite a few do. One guy (Mikey Chen) even left the session three times to “pee”. Three times??