Suspicious scores in a flash game

This is an interesting one, I wrote a Yeti Penguin toss clone a while back, thoughout testing it, and for as long as I can remember the top score you could get was in the range of the 500m. Recently, it has been reseeded and a select few people are getting MUCH higher scores (at least double previous top scores :-/ ).

Obviously, people decompiling the SWF or tampering with the back end is a possibility, I was wondering if there is anything to do with Flash that might be causing this? Maybe frame rates, overclocking(?), different browsers/OS etc. Anyone got any ideas?

I dont have the code to hand (its backed up somewhere at the moment), but I was wondering if anyone had some suggestions what it might be?