Usually, warning the devs before anything happens if you have a suspicious looking setup is a good idea. I have two keys, one of which I used to play cRPG for about 10 minutes, then I gave it to a friend.
Interestingly, it was a steam version of the game. So I only had the steam key, but I found the actual warband key in my windows registry, and you can actually give that one to somebody. You can even buy the game on steam, get the key, uninstall your steam version, download the game straight from taleworlds and activate it with the key you found.