Include the CCR in your lease and have the tenant sign that if fines are incured due to the tenant behavior, the tenant will be in breach of the lease.99% of the time the tenant is doing one of a few things: parking in a red zone, having loud parties, bringing to many guests to the pool, unsightly belongings visible, unsupervised pets, not leashed, defacate in the common area, unsupervised children (that make noise and break stuff), speeding in the deiveway, bringing food, glass, beer or marijuana (legal in CO but not CA) into the pool area, indecent or illegal activities in the common area.I've seen it all.

Since she is exhibiting what I would call "attacking" behavior ... this could wind up costing you lots of money if you allow this to continue.    

We'd be having a "talk" about that behavior and hopefully come to an agreement right then and there, and document said agreement. 

Live and learn.And, their ex will be around, maybe move in, move back out, screaming fights, furniture being thrown in the hall - professionals are not immune to this behavior.

Then, maybe you can get them out for criminal behavior?

Your behavior can be considered a waiver of the terms in the lease requiring rent on the first.  

You did the right thing.Next time just remember to meet him during business hours.People's behavior is always interesting when it is time to pay for a service, I have stopped assuming things.

To that end, you may request from the tenants that are being disturbed that they provide some documentation of the behavior that has occurred. 

Then you are not open to all pets yet not closing off the possibility altogether....So, for example, one small well behaved dog you may approve  (especially one that a previous landlord says was not a noise, damage or other problem) but a pack of loud unruly ones not so much...And you can refine some of what you are looking for in terms of size, behavior, numbers, breeds, ages (no puppies without house training for me, eg), even spaded/neutered (especially for male cats, etc), references (ie how the owner did with a pet in past places), etc... 

Given enough time and lots of good behavior, she'll be able to eventually improve her situation.