An address is already PII, whether you pseudonymize it with apartment numbers or not.

Also I think in practice the bigger concern with IPs is that the IP itself is PII at the time you collect it, so you're always processing PII even if the hash or other such "anonymized" data you store may end up not technically being PII if there's no way to correlate it to an actual person after the fact (which wouldn't be the case for a simple hash which can be deanonymized with rainbow tables).

> An address is already PII, whether you pseudonymize it with apartment numbers or not.

The full address is PII. But a street level address isn't necessarily, if it points to an appt block.

The problem with the mail boxes is that you're leaking that a "Mr. Smith" is living at that address. Now with Mr. Smith this is not such a big problem but if you're looking for "Mr. LessUnique" then it is

If you're arguing that landlords should have to get written consent to post a tenant's name on the mail boxes and door bell, then I agree. If we're talking about tenants doing it themselves, then there's no privacy issue unless someone else collects that information and uses it for other purposes.