Just about all the arrivals at the PFA Rally will not have a clue that they are supposed to conform to this. What are they going to do? Not get out of the aircraft? Of course they will and there won't be enough marshallers to stop them. So the whole thing will become unenforceable.
The only way that you can tell who are marshallers there anyway is because they are (were) the only ones in yellow jackets. Now aircraft will be following anybody in yellow who is waving their arms about. Chaos will result when many hundreds of aircraft are parked all over the place.