How to handle re-buys

[ChuckyB]

We play a weekly tournament with a pretty regular group. If someone comes late, and we know they're coming, we blind them off until they arrive. But when the blinds are 25/50 out of a 5,000 stack, it's pretty meaningless.

We've run into a problem with handling re-buys when the blinds get higher (ie. 200/400). Players will get knocked out, go for a smoke and then re-buy. That seems wrong, because other players are essentially playing short-handed and risking their chips, while the re-buyer risks nothing.

Should we make players re-buy immediately...then if they want to take a break, it's at their own risk? How do you do it?