Bukkit

Our server uses this plugin for player shops. Lately there has been a increase of players scamming others for high amount of money. Is there a way to implement a sort of safety net like use chat to write yes or no to the purchase of said item?

That's an interesting feature, not sure if it really is necessary or if it would just be extremely annoying for the players. So there's no ETA when this could be implemented by me but I'll leave it open as an Enhancement.

Generally speaking you should advice your players to be more aware of the signs they click on (that worked for my server) or let players split their money between a bank account and their normal one.