So the issue here is noise and how that noise is affecting the right for peaceful enjoyment of your other tenant.  

If college students are going to cram 5 full-sized adults in a 3 bedroom/2 bathroom home you'll get a lot of wear and tear, parking is a pain, noise complaints in a family neighborhood, the occasional kegger, etc.

And it's infinitely harder to kick out a tenant for breach of lease agreement - say for excessive noise, or guests that scare your other tenants, etc.  

She actually wanted me to tell another tenant to get rid of their air conditioning unit, because the noise was bothering her.  

but its just saber rattling and it worked.. you cant see the inside of a court room without both sides spending at least 25k each. highly doubt that will happen..    

They're noise nazis or plants on the balcony nazis or anti-rental nazis.I owned one for about 3 years and made a profit, but couldn't WAIT to get out from under the HOA, and yes, I even got on the board to try and add some experience/sanity to it, but it was a losing, insane battle. 

It may be the case that in the recent past the "noise" seemed to indicate that there were more of one kind than another - cash flow only, appreciation only, refi till you die, etc - but if you look beyond the noise to the signal it's a pretty steady drumbeat straight through.  

-Noise is VERY difficult to evict for.  

I hate the pens that make a noise. 

Oh, that noise you heard?