Do you not see the obvious problem this will create? What's to stop someone from open shoving 500 points 5x's to get quick folds at the small buy in tables?
Yes you can go all in to try to get through your rollover. You can also get called and lose it all. It will be fun and thats what its all about.
As far as US guys playing and winning or losing in real money games; the US guy starts with loyalty points and he is free to try to run them up. The key is he never bought anything. If he loses he will have lost nothing so he did not really gamble...he simply participated in a loyalty program.