Just a thought, but shouldn't the reward be in BTC, since if someone finds a way to break Gridcoin, the 5000grc reward will most likely be worthless.
Love the idea of this altcoin though. Hopefully it will pass the test of time.
I'm from the camp that believes it would be worth more if an exploit is found because we will fix it.
I think there is a similarity here to something feathercoin went through at one time when they had a security issue and their exchange rate value didn't change much and they fixed it and moved on.
Rob H.