It's a bit of a gray area, but there's likely no wrongdoing here.

A dealership employee is seen unplugging a Tesla Model 3 that was charging at a free charger. Is that okay? Or has the dealership done something wrong?

This is kind of a murky area since dealerships often have public, free chargers. However, the general consensus seems to be that those chargers are for owners of plug-ins from the brands sold at that dealer.

Often times, dealerships won't care if you plug in a different brand car. In fact, my local Ford dealer has no issue with me charging my Chevy Volt on their premises (for free!), but this shouldn't be expected, nor should it be abused.

Therefore, in this instance where a Tesla uses the charger for free night after night, we have no issue with the dealership unplugging it, but perhaps we're in the minority here. Let us know your thoughts on this in comments below, but before you do, take a glance at the YouTube commentary directly below first.

Video description via smvballer6 on YouTube:

Parked my car to charge at a Dealership and this is what happens...when I leave, this guy takes away the charger that is free to the public, smh. Model 3 Tesla

The comments on the YouTube video provide us with some additional information. Here's some of what was mentioned:

Federico V:

Are you sure the charger was free for everyone? it was a ChargePoint or similar service? some dealerships only offer this to their customers (in this case VOLT/BOLT owners). I'm saying this because he looks like he came only to disconnect you, probably because he got an alert that someone was using that charger (maybe the supervisor of this dealership?). His shirt it looks like is from where he works...
 
smvballer6

Federico V great question! I always charge there overnight due to the fact my wife and I live in an apartment. They never seem to have a problem, but I try to stay out of the way. Maybe I didn’t this time.