I think the community is based on trust and at the end of the day sketching is more about learning, having fun and doing something in parallel with the community.
Robbing mods, in my opinion, is the ability to participate in the community that they (voluntarily) maintain.
I don't think we should be suspicious or check metadata or prevent mods from taking part in the challenges. Just do cool things and have fun.
If the sketch has a larger context than this, say a challenge for some (prize) or (reward), then I think it would be good to keep it fair in the sense that only non-mods can participate.
Thank you for all the help and work you are doing for the community