I've found (and dealt with) a handful of accounts that consisted of the following:

Account "A" playing the game.

Account "B" created. All new funds sent to account "A". Account "B" mines a bunch of jewels, trades them in (at a great prices), send them to Account "A". Repeat.

It's easy enough for me to sniff those out, but I'd rather not spend my evenings dealing with this crap.

One possible solution is to not allow users to deposit funds in another player's account until they've accomplished "x" (troops, day, etc). Any thoughts?