I have to say I was being very parochial and only considering chess. Games like backgammon with an element of chance mean that the ratings have less significance (I know skill level should mean "more likely to win").
And not all ratings boosters are bad players!
One thing i have found though.. playing honest players the relative rating positions work in regard to win loss ratios....
Last point .. players who occaisionally make really dumb moves are clearly not relying on help!