It prevents these sorts of problems

You might at least file the contract with the county, which would prevent him from selling to anyone else.

Banks will often place deed restrictions on properties they allow to be short saled to prevent the property from being flipped.

@Emmett FosterThis automated response is in-place to prevent spamming of BP members by agents - human of virtual - which sign-up for an account solely for the purpose of sending solicitations.If you send out too many private messages w/ or w/o colleague requests within a certain time frame, the system will flag you as misbehaving.

Whether or not we ever get to take advantage of that, I'm trying to learn to live a healthy lifestyle now in order to prevent health problems later on in life.

It clouds title and prevents this very thing from happening.

if you could do that on an abandoned property, what prevents people from doing that to any place ?

@Rocky V. makes total sense, being open and preventing headaches down the line.

There are regulations that prevent my lending on those.  

If a contractor says they will fix A, B and C within 3 months for 25k, is there any way to prevent them from saying oh, sorry, A, B and C will actually be 30k, we also need to do D and F which will be another 15k, and it'll take us 5 months?)