Before even meeting a tenant, I let them know that we will do these things, and let them know our requirements: 3x rent in net income to be verified before lease signing, no criminal history or evictions, no bankruptcies and good landlord references. 

First offence contracting without a license is a $5,000 fine in these parts.

But make sure you do all the credit, criminal, eviction checks you can.

If I end up having to replace just this one guys entire section of fence at one point it would cost 6K+.

Maybe go after them for criminal fraud, maybe tell you it's civil, maybe tell you to make better business decisions. 

You may be better off just reaching out to the contractor's board for possible criminal remedies.

Just remember trans union or anyone else cannot run a national criminal check only law enforcement can and all they are doing is running a prison check and calling it a national criminal search. 

For $25 you'll get a criminal background check, credit score, and an overall recommendation based on criteria you set.

It means that you cared more about turning a profit than in creating a safe and legal dwelling... and behaved in a criminal way to conceal your misdeed. 

If they have a clean criminal history, a great rental history and stable employment then they hit all the key points for me to be able to approve them.