At lower levels (25k-15k), I really think that score estimator can influence a game. A lot of players seem to use it to help them see living and dead groups, to me it really look likes an external help. Any go player should be able to calculate by himself his score during the game, and see living and dead groups. I mean, it’s the purpose of the game after all. Score estimator is very useful to help new players learn go rules, but it should be deactivated by default during live games.