Red thumbing someone is definitely more efficient than the approach of one player I know of. This player beat me repeatedly at one particular game, which has a smallish pool. Then came the day I won against them, and by a big margin. After that, each time I joined a table they had set up, they would quit it. A couple of times they joined my game, to hastily leave it again when the confirmation screen came up. I thought I was imagining it at first, but it happened so consistently that I don't think I could have been.
I gave up attempting to join games with them, until about six months later I saw they had opened another table and joined it out of curiosity. Same thing happened again. Truth be told, I'm a little impressed that someone could hold such a feeble grudge for so long and has never realised the potential of the red thumb