There are other types of "sandbaggers", the ones that have various accounts.
Making a new account (with a new rating), gives them no problem in playing tourneys as under`rated players (because they "didn`t have the chance" of improving their rating).
Last days I played in this type of tourneys (points handicap), I saw a lot of players with accounts made in august 2011, having 1600 - 1700 rating and playing like a 2200+ at least.
This is why I propose having a lot higher minimum experience level to enter this tournaments, like 50-100, of smth like that(from what I saw, now it`s 7, which is really easy to get to).
Another thing that I think should (if it could ) be implemented in CC system is a program that automatically kicks out from any tournament a guy with a difference of ratings between general and tournament higher than .. let`s say .. 250. It could be like a checking when he tries to enter a tournament and not letting him in if he doesn`t pass this term.
I think this could save a lot of work from you too, checking everybody and banning them for sandbagging (after they`ve already damaged the tournament) and maybe make them better people
Doing these 2 things, I think could improve a lot tournaments playing and the FAIR PLAY.