This was never a bug. Some sites do allow you to place a bet over max profit and some don't. The system we had in place allowed you to place these bets
They knowingly allowed player to place bet, yahoo placed whole $300+. They accepted that bet. So how OP screwed them? He won?
The main problem is asymmetry.
If yahoo lost his bet, he would just lose ALL his money and the conditions of the bet would apply. However, if he won, he would not win the full price.
This is dishonest. You know the code wasn't properly designed and you let it run online anyway, hurting players money and balance (when users misclick or when they are newbies).
That was exactly my point all the time, completely lame really... I have said enough though so now I am really out. Glad someone also agreed that this is the worst thing about all this.