Sounds a bit fanciful to me and, like Dick, I see the 'freeman on the land' gang getting aroused just thinking about it.
Now Nick Freeman is a very talented solicitor and is quite adept at getting those who suffer from the mighty few bob off of motoring related criminal charges like speeding and drink driving. Parking however is a different animal. It's a weasel to be precise and is administered by weasels.
The theory behind it certainly stands up and has a sense of legitimacy about it. We have encountered at least a couple of times on here cases where travellers have invaded a council car park and have not been ticketed. Regular users who were ticketed raised the issue with the council and the council's response was along the lines of they cannot ticket the travellers because they are there illegally. It all sounds like Mr Freeman's master plan is coming together now except that the council would not tolerate regular people doing this. I'm pretty sure (shoot me down in flames if I'm not) that Council car parks are not (or are not supposed to be) governed by contract law. They are part of TMOs and are subject to unreasonable target based enforcement (I'm not wrong about that last bit so don't even go there). My feeling is that the Council gave a stock spokesweasel reply because it sounded better than "we can't be arsed ticketing them because we've got more chance of getting a straight answer out of Patrick Trouserfire than we have of getting a traveller to pay a PCN we issued to a car that is probably not even registered to them.
So if you were to try this out,
and I seriously suggest you don't, you would be following a theory devised by a very knowledgeable man but not necessarily in the area of law you are invading, based upon a letter from one single MP to his constituent. Here's what I think would happen,
1. You would be issued with a PCN
2. If your representations were based on illegal occupation, you would lose and be ordered to pay. If you didn't pay the Bailiffs would come round and remove goods to the value of 10 times the original PCN and your first born would be sold into slavery.
2a. If you refuse to engage in the appeals process you go straight to the Bailiff stage as above but you exact your bloody revenge by filming all your possessions leaving your property and uploading the footage onto YouTube so that all your freeman on the land mates can agree how unfairly you have been treated. This will have to be done on a mate's computer since yours was taken by the Bailiffs.
3. The information the MP gave to his constituent was sadly given in error and whilst the Council sympathise with your position, everyone has had a truly splendid drink at your expense.
On the other hand, I could have this completely wrong and we have found a sure fire way of avoiding paying Council parking charges, three or four quid in some cases.