OK, now I remember the original legislation.
I agree that the input of the Forum Administration is a good request to make as this is largely a technical issue by nature.
IIRC, the original issue that brought this to the fore way back when, were accounts created via an anonymous proxy server with the intent to create multiple identities on the forum (which would, in turn, allow someone to vote multiple times).
The deception issue is the real question. If someone needed for one legitimate reason or another to sign onto the board via server that is essentially a proxy server there wouldn't be a deception involved. That said, anonymizing proxy servers are a "no-no" as per the rules for obvious reasons. If there is a legitimate reason to use a proxy server that provides anonymity (intentionally or otherwise) needs to be used, the user should inform forum administration for approval.
If a known user signs in via a proxy server, it can generally be assumed that the user is not doing anything untowardly because it can be generally assumed that only the real user of an account would have the password of that account. This, by the way, may also be considered as prima facia evidence in prohibiting proxy servers altogether because were I a hacker who somehow got a user password, I would use a proxy server to cover unlawful access to cover my tracks.
And this is why the original legislation absolutely prohibited proxy servers.