A note is evidence of a debt.

I was in eviction court once watching a case when the tenant presented print-outs of text messages regarding repair requests as evidence.  

You'll need to use tenant A to gather and send evidence of tenant B's behavior to you and this will put them in an escalating adversarial position.  

Once he sees how much he will owe to remove any evidence of an animal in the unit, he will probably tell his friend not to bring the dog any more!

My hunch here is its OK because it is quite evident that the owner is as good of an owner as you can be and that they are following the Milwaukee code as they were completely caged. 

If you have a company party and feed your contracts for example, record evidence of that party, have them sign a guest roster, might show the reservation for the place you use.

@Bob Bowling Hi Bob, I'm not using the article quote as evidence whatsoever.

As long as you have evidence she received and the damages you deducted are documented you are fine. 

IANAL- but glass pipes and "appearing high" would likely not meet reasonable cause for a warrant, as would evidence of distribution or sighting of actual drugs.Personally, if they're good tenants who pay rent on time and are employed, I wouldn't do more than make a mental note of it.

This is evidently what the tenant hopes for.