The losing party want to receive 0.1 btc for the lost side.
We can rise it to 0.2 btc or to 0.5 btc if you want
So: I lose. You win. I get 0.1 BTC, you get 5.9 BTC. If I do not sign, we both get nothing. I'll make you an offer you can not refuse: pay me 2 bitcoin for my signature code!
You can see the flaw in your system.