As long as my rental income is taxed, you can bet I'll make noise about preventing these rent controls that are inevitable in Chicago should the ban be lifted. 

Have a plumber send a camera down the line and then grind out the roots.

She was upset and apologized to the girls, however, now it seems she has an ax to grind and literally calls the police for every little thing they do!!!  

Over time this a possible maintenance and failure point, wastes space, makes noise, needs professional plumbing skills to have done properly and costs a lot of money.

It seems that, like "John Smith", you also have an axe to grind.

Hey Michael, I'm happy to hear about your new pursuits in RE, and it's good that you are honest about the about level of grind it will take to get traction against the big dogs out here in Denver-Metro.  

Keep making noise with city officials until they hear you.

I just spent all weekend with a rented tracked skidsteer loader with a monster bushhog cutting this bamboo down and grinding it up . it was more than my kubota's bushhog could handle , I still have at least another day with a york rake to clean up and pile the stuff up .At least I can pile it in the back of the lot , it would fill about six 40 yd cans .The fun part was this skidsteer and bushhog ripped thru the bamboo and it would grind up 4 inch saplings , I knocked over a couple trees roots and all came up .

Keep Grinding!!

If they already make threats to sue for normal maintenance,  its not a stretch that they would just make more noise about having people walk through their house.