That's definitely a concern and something we'd do our best to mitigate. On the one hand we could put into place a lot of controls and a reward system based on performance; or on the other, we could take a fee market approach relying on the transparency of the platform to deter abuse.
It takes an incredible amount of engineering work to put something like this together, so that's why it's been something that we started working on back in early 2009. One of the things we've working hard on doing is making it really simple to share your trading. We already have entry via FD and MetaTrader (using an EA) baked in, and we'll be adding our own order entry API and direct integration with the broker shortly (using the broker credentials).
Sounds cool.. I'm always open to new ideas =)