yes probility
Reliable Method To Play As White >50% (?)

Yeah, they'd have to look at your history to prevent this, which will have some non-zero computation cost.
But it's probably not worth preventing, because I imagine you'd almost certainly be between 50-55% in any case.
But I thought it's an interesting idea.
I recall a mod / staff member saying that when you seek a game, the color is random. In other words it's not looking at your history, it just randomizes the color and the law of large numbers takes care of the rest, pushing your colors close to 50/50. This method makes sense for multiple reasons.
But if this is true, you could use this to get more whites by offering / accepting as many rematches as possible after you've played as black (and none when you've played as white)... because that way you'd be adding white games.