I have also been annoyed by sandbaggers--5.5 players playing 4.0 singles at the state tournament.
HOWEVER, I'm sorry to tell you that I'm contemplating throwing a match and sandbagging a little myself. Here's the situation: When I was bumped up to 4.5, it ended my league tennis career. There are no 4.5 teams around here, so if I want to play, I better protect that 4.0 ranking. Sandbagging sucks, but it's better than not playing at all.
The system works great at the lower levels, but when you bump into the ceiling, you have to throw a match, or you'll be sitting at home every Saturday while all of your friends are playing their league matches. The worst feeling is when Saturday morning is the only time all week you can play, and all of the people you want to play with have a league match.
If the world's #1 player was automatically banned from tennis for life, would Roger Federer want to be #1, or would he throw a match here and there so he could keep playing?