Well... As someone who organises a show, here's what I did/do... When the law came out, I got completely hacked off with it... yet another way for Westminster to tell us what to do. But, wanting to be a law abiding citizen, and not wanting to land myself in hot water, I asked the advice of our local bobby, since he would be the one with a responsibility to investigate should a complaint be made.
The long and short of it is that the police obviously have enough to do without going to shows looking for tails and establishing the ages of dogs. However, they have a responsibility to invest