Everyone was just rolling with the punches there for a couple years. 

Generally speaking, with SFR or small multis, I just rely on the lease/rent roll (and some form of proof of payment; i.e. bank statements, deposit receipts, tax returns, etc.). 

Just one additional option.  

At least 8 rolls of TP plus 4 in the closet they can access.

Selling your share at fair market value could avoid gift tax but may trigger capital gains tax for you based on the sale price and your cost basis.In California, the transfer may also trigger a property tax reassessment under Proposition 13 unless a specific exemption applies.

Saying it wasn't in the lease or @Kevin Sobilo saying it just comes down to one person's word against another would negate virtually every crime.   

Again, the one side thinks it's funny until it hits them.

The good ones will have access to off-market deals. 

Instead, roll the funds into an IRA or Self-Directed IRA (SDIRA) to keep them tax-deferred and open up flexible investment options, including real estate.

Comps can show one thing but actually closing can be another.