Nope you don't have to bet, just have it select "friendly duel".
The problem is that the bot would have to recognize the main account to challenge it to a duel.
Alternatively, it could just be made to respond to duel requests and go that way. This way all it takes is for me to manually challenge the bot on my main and the bot just clicks the request, clicks accept 2x and then forfeits.
Hmm.... seems easier that way.