Since Ive heard/& had myself accidental usage with gems
My suggestion is that for every rush to builders You must enter a 4 letters code to confirm it.
I once had the game running in my pocket and it accidently used all my gems for some gold which i absolutly didnt need.
This feature can save alot of frustration from players and keep everyone happy
Doesnt have to apply on barracks and drills boosts since they dont cost too much anyway.

