The presence of a controlled substance is hard evidence, while these other items are not so clearly defined. 

@Will Barnard- hey man what happens if you do have "evidence of termites both subterranean and drywood", but no actual termites?  

I would still file a police report so that you have that for documentation/evidence if it does blow back on you

A good lawyer would use this thread as evidence of notice.

Accordingly, you should always secure valid evidence of insurance from all contractors that work on the premises.d.

I photoed the evidence and the broken disposal and sent the tenant a repair bill just like any service provider would.

What evidence do you have, other than her word, that she has a good rental history?

That's why it's so important that you do everything you possibly can to ensure that if the IRS ever audits you, that they have as much evidence as possible to conclude that someone working for you is an independent contractor, NOT an employee.

Yes they maybe a little more expensive than a mentor, Craig's list or newspaper ad responder, but you will be assured of a quality inspection, good photographic evidence and the security to know that if them miss something ... they have insurance to cover it.

If you had any objective evidence you could link showing the correlation you mention I would be interested in seeing it.