@Bob AnthesHey Bob, I use Bradley Cotton with Cotton Property Management.

I dont remember using a pad but th runner was a pretty thick wool one.  

@Alex Cotton made a good point about not rocking the boat if they are quality tenants.

Again, absent the details of your tenant's personality, I don't see this as an attempt by your tenant to "pull the wool over your eyes" or take advantage of you but rather them keeping a mindful eye on their security deposit.  

Rock Wool is often used in apartment buildings partial for its ability to dampen noise.

Stick to your criteria, and then nobody can pull the wool over your eyes.

@Jeff Cotton the only thing I would add to what @Bill Gulley said is that you get what you allow.

We use steel wool to fill the holes, then cover the exterior as normal.

Fan is wired with a humidistat and timer, so we need not worry about tenants either not tuning it on, or turning it off when they leave.What you do not see in that picture is behind the walls - when renovating a bathroom we put 3" rock wool (Roxul Safe-n-sound) batts in all the walls to provide sound deadening and, in some instances will use 5/8 drywall and resilient channel.  

Eventually, I stuffed some steel wool into the crack and I'll go back there in a week or so with a bag of concrete and a tub to make a full-on tenant-satisfaction pantomime out of filling that crack and protecting her against the terrifying concrete-tunneling squirrels.