Interesting, yeah I was very cautious about that.

Be cautious and verify. 

That being said, from a landlord point of view I would definitely be extremely cautious if dad will not cosign.

I want to be cautious, but dont want to pass on a good deal because of mold.  

I would be cautious and dig a little deeper.Being in a city on the state line, common reasons for people not changing their driver's licenses or vehicle plates here include: evading paying registration fees, evading paying sales tax by showing an ID from a state that has no sales tax, evading being tracked down by creditors, evading paying child support, evading the law, planning to move back to the other state soon (short tenancy), wanting to retain some of the benefits of the prior state (library card, voter registration, tax privileges, etc.)  

I have too many things to juggle right now.You are not superstitious... just cautious. 

I don't allow smoking so many of these would be out, but if I were you, I'd be really cautious about discriminating on the basis of people having illnesses / needing care (disability), having 4 kids (family status), or foreign language ability (ethnicity).

California is one of those states where landlords need to be extra cautious.

The tenant may have a perfectly reasonable explanation for their behavior and perhaps your relationship would be entirely different once you are the owner but unless you get that feeling you should take a cautious approach and have them removed and the locks changed prior to closing. 

I'm an overly cautious person though and would want to know what the legal ramifications would be.