Quoted from tomtest:Nudging is cheating, never shake a machine unless you are a very poor player!!
Tilt warnings are a resource, like lives in a video game or gold in Dungeons And Dragons. If you aren't taking advantage of them, it's a waste. TNA actually gives out extra tilt warnings in the mystery award.
But in regards to the original question, I only know one A Division level player who likes sitting while he plays and it depends on the game. He usually does it when playing early solid states or EMs. And I've seen him tilt while sitting.