Yes that will make the Farnborough Air Show impossible. It will be very difficult to observe/monitor the major roads around Farnborough and Aldershot M3 etc.,from the airfield, without many observers off site.
Unless of course there is one CAA rule for small shows and another for others.
This knee jerk reaction by the CAA will be the nail in the coffin for many more air shows this year.
Changing display gate heights mid display according to the local traffic, as happened at displays post Shoreham last year, is very dangerous in itself.