Floor monitoring guards in NSW quarantine hotels do not always (in fact IME rarely) wear masks or other types of PPE whilst undertaking floor monitoring activities.NSW test HQ workers every shift, but realise unless you lock HQ workers in permanent ISO they are going to be in community. So PPE, training in procedures, surveillance and testing every shift are the controls.
The guards sat outside my room, and when I retrieved my meals I noticed it was rare for them to actually be wearing a mask (I did just for the few seconds I had the door open ... a bit irrational but why not?). Some did have surgical masks on and many wore surgical masks over their chins (presumably in case of inspections), no N95 masks though. I bet the same in other states too.