I tried to only buy anything less than 20 gems but still got banned after 2 hours. (I was banned when the cheat wasn't active, so it must be something I have done before that)
What I did was:
- boosted building time (1-8 gems each)
- Upgrade building with gems (very little amount, usually less than 15 each)
- bought energy to do tournament (I bought 5 energy each time) -> was just enough to get 33 consecutive wins (to get the golden keys) and ranked 730, still pretty low
- bought energy to do epic boss (most I bought was 10 energy each), and just enough for the quests
- buy energy to summon boss for materials (at most 16 energy each)
- By the time I was banned I was at level 29, and had about 1000 gems. I never buy anything from the chance chests yet, with nor without cheat.
What did you use your gem cheat for?