"Not before 12.00 pm" - Difficult to

Apologies if this is raising an 'old chestnut' but  I cannot understand why some members believe the instruction in the handbook "No arrivals before 12.00 pm" does not apply to them. Equally I cannot understand why wardens allow people 'on site' before this time.

Yesterday we returned from 10 days in Devon at the Ramsdale site.The site was excellent in every respect and the Wardens / Assistant Wardens were extremely personal, helpful and friendly.

 Our pitch was the 1st on site so we were able to see people arriving (and no, before anyone comments, we weren't curtain twitching). It was however noticeable that arrivals were coming in early. One day, having my second cup of tea at breakfast, I noticed that not 1 but 2 vans arrived at 10.00 a.m. another 3 arrived before 11.30 a.m. Sadly this was not an isolated morning  as the same thing happened on 2 other days, with people arriving 10.15 and 11.00 a.m. (Why were we still in? Because it was raining)

Bearing in mind the location of the site is on a narrow lane, rather extreme in places, it put the wardens in a very difficult position. What were they to do?(1) Ask people to drive round the site,go through the exit  further along the lane and come back later (2)  ask them to wait until 12.00 pm in the arrivals area or (3) allocate a pitch and allow them in?

Now some will argue that if there are pitches available option (3) is what should happen and the sensible thing to do.  I can see that, but unless wardens are firm and 'inconvenience' those that arrive 1 hour or in this case 2 hours before the correct tme, they will continue to continue the practice.

Any constructive ideas how this behaviour can be discouraged?