What a pain. Can this person not see that routine breaches by a committee member undermine the whole governance of the building.
Maybe a personal approach of the ‘Mate, you’re putting me and the committee in an impossible position by blatantly breaking the by-laws. Please knock it off.’ However he responds, you can simply point out that the building is unmanageable if you can’t rely on everyone following the rules. Either way, it should get to a point where he either acknowledges this and agrees, or he outright says ‘Stuff that, I’m on the committee so I can do what I want.’ In which case, you know where you stand with him.
Or perhaps you need a few more by-law breaches (perhaps someone else parking in visitors’ spots; piling stuff up in their car space; leaving things in the foyer or hallway…get creative). When they come before the committee you can ask ‘how can we ask one person to comply when we’re not asking everyone?’
I’d be declining to be on the committee with them at the next AGM. It’s hardball, and depends on how much others in the building value your role, but I’ve done it successfully when a serial late-payer and pain-in-the-neck owner nominated for the committee. He got smart and withdrew his nomination before it was put to a vote.
Of course, whatever you do, you can save it up until the ‘critical infrastructure’ matter is dealt with. Then just tell this person: ‘Now that we have X dealt with, stick to parking in your own spot.’
Perhaps make sure your other committee members don’t see taking action as ‘inflaming’ the situation. Their flouting of the rules has done all the inflaming. And it will be obvious to everyone in the place.
Good luck!