Why?
Well it’s always sounded a like a bit of a stretch to me, but as the common property is considered a workplace when maintenance people and others are on-site, the situation is covered by Sect 10 of the NSW Workplace Surveillance Act (2005).
I have complied with respect to our Strata Plan by placing a CCTV symbol and a prominent notification at the bottom of all Work Orders which are always issued 14 days in advance; no repercussions so far!
One further point that may well be a furphy, is that the placement of those “property under surveillance” signs around the common property could lead to legal consequences for the O/C if residents then rely upon those for their personal well-being and for that of their personal property, and then find that when the worse happens – there is no surveillance.
Just putting it out there!