Proposal: anyone found to have lied on their account application will be banned. Or, alternatively, their case will be brought up to the editors and a consensus reached by the editorship.
(as a reminder you can see the questions here: https://en.prolewiki.org/wiki/MediaWiki:Requestaccount-bio-text)
This should be made clear in my opinion so as to reduce confusion when it will inevitably come up in the future. It's a simple one line rule that essentially takes care of every problem we might come across.
Lying in this case would be contradicting oneself. For example if someone says they support Stalin in the account application but then edit pages to add in liberal anti-Stalin criticism.
This would take care of wreckers and other infiltrators as well as agendaposters and probably even cases I can't think of right now since we haven't had to worry about them yet.
Tbh I feel this is pretty much how we operate already, and I'm a big proponent of formalising stuff we do informally for transparency and later reference.