I don't think a service or emotional support animal is required to have any vet review, but you should be able to request verification they are up-to-date on shots, etc.Emotional support animals can be cats, fish, snakes or any other variety of animal.

Can I float an owl or snake balloon up into the tree and scare off the birds?

The water costs absolutely nothing in comparison to what I cost with a snake and a bad temper.

When, all that it really needed was to be snaked. 

I'd double check vents, and perhaps take a snake camera to the drains within the kitchen.  

Anyone who tells you they've seen everything in this business is either fairly new to it.... or a snake-oil peddler.At the end of the day, it sounds like many of you have had bad experiences with Property Managers.... and I'm truly sorry about that.

Though I do know how to operate a snake and have done so on many occasions...

Now, if she was stuffing "flushable" wipes, and we all know there really is no such thing, and you've explained to her that she can't flush flushable wipes and if it happens again and the snake brings up a wad of flushable wipes again - then she'll have to pay the bill - that's reasonable.But, to charge her for a problem because you can't figure out how it's happening - well, you'll end up with an expensive consequence.  

Contact whatever licensing board is appropriate and sue them in small claims court.Had a similar situation at my daughter's rental property, where the PMC did the video scope that found cracked sewer line blah blah.We hired someone to snake the pipes - problem solved for about $100 as opposed to the $5,000 they were quoting including tearing up the street and city permits on and on.

It is not "snake oil."