I'm pretty sure doing janky things to the AC you don't own is a lease violation.
I'd gladly let them keep the security deposit so that evil companies like RealPage don't blacklist me.
I'd gladly let them keep the security deposit so that evil companies like RealPage don't blacklist me.
Why? Not all "janky" things are the same:
* Sloppy changes to the internal 240V wiring: yeah probably a violation of the lease, and legitimately likely to burn the place down, with associated liability.
* Temporarily mounting to the exterior this mechanism that turns the knob shaft, with no changes to the wiring, no holes, no nothing. I can't think what grounds they'd have for considering this a lease violation or a reason to keep any of the security deposit, as long as you pop the original knob back on when you move out. And as inigyou pointed out, how would they even know?