A little bit of stretching of the rules has been common knowledge for years. There are cars that always seem to have a notable advantage over others that should be broadly equivalent. Not all of it could be down to driving.
It's clearly come to a head and maybe someone was particularly taking the mickey. There have been some test days over the last few weeks and maybe a car had improved by a suspicious amount.
It's a good thing. One of the things I cherish about the Revival is the traditional look of the circuit and the unimpeded view. However some of the cars are now fearsomely fast and particularly since they let the contemporary touring car crowd in, the racing can be uncompromising. The last thing we need is a big accident that injures spectators. They've already beefed up some of the fencing around the circuit.