First of all, I don't know which rabbit club had the display at Rudgwick, so I can't comment on the set-up at this show!
But I'd like to say that, at the shows I have been to where there has been a "For Sale" section, it has been very well run and the quality of advice is better than many pet shops!
First of all, the sales section at the shows I am familiar with is managed by fanciers who are doing this voluntarily, and are experienced. The rabbits on sale are all checked over for problems such as signs of illness, or bad teeth, are sexed and will not be accepted for sale if there is anything wrong.
The rabbits are sold according to the BRC sales guidelines (as mentioned in another thread); in brief, this means no sales to anyone under 16 without parents present and giving permission, and the rabbits are not sold under 8 weeks of age, as well as the other considerations outlined in the code of practice.
The buyers also given the name & address of the seller - and the seller is given the name & address of the buyer after the show. If the breeder/seller is present at the show (which they usually are), they can be called over to answer any questions the prospective new owner may have and meet them face to face.
The new buyers are given care sheets, quizzed on what kind of accommodation they have at home; given a week's supply of food, and provided with a strong, well-sized cardboard box filled with bedding & hay for the journey home. They are allowed to handle and examine any of the rabbits for sale, without obligation and with no pressure from a salesperson.
They are also permitted to leave the rabbit they have reserved (or paid for in full) until after the show if they wish, meaning that the family or individual can have a "cooling off" period; come back later and change their minds if they wish.
In addition, the sales staff know their breeds inside out, and can advise on specialist care for the rabbits on sale, including the proper care of long-haired breeds! And they will not sell to "just anybody" either - if they are uncertain or suspect the person is not genuinely going to care for the rabbit, they can - and will - persuade them against it.
As I said to start with, that is how I have seen my local rabbit clubs manage their sales at shows; I don't know who was in charge at Rudgwick.
All in all, I would say that it is managed much better than many pet shops; in fact I can only think of one pet shop I've ever seen that takes this much care and provides as much to new owners.
Having recently met someone who bought a long-haired rabbit from P@H with little advice, not even told it would need grooming, or how big it would get, and was allowed to take it without being asked if they had anywhere to put it, and given no guidance on suitable housing... not to mention not being given its age, and nobody noticed it had a bite wound on its face... I think I'd have rather advised these people to try a rabbit show instead!