He is unlikely to challenge you in court because that would be admitting to something illegal.

(And would this be more challenging for the courts?) 

Been in this rollercoaster ride for about 11yrs, Love the challenge from negotiating with lenders (shortsales) To dealing with multiple sellers with different mindsets. 

If you are looking to buy something off of the local MLS - you might find that is going to be a challenge.  

The bigger challenge is likely to be financing, fnma, freddie, HUD aren't going to touch that - giant marketability issues.  

If not, then you could challenge the fine.

For me its a challenge to get good contractors and handymen.

So far i have faced quite a few challenges, mostly from my wife and her parents.

If you'd like to download it for yourself, play around with the inputs, or challenge my assumptions and model, you may do so in the BiggerPockets fileplace here:https://www.biggerpockets.com/files/user/ScottTren...Hope that helps!

It's pretty challenging to put a deal together when you have absolutely no idea what's going on with the other side or with the property.