What a balanced argument in this thread. I am straddled on the 'wall(s)' as always.
The bottom line is, people should know there own animals and make safe any dangerous situations (unless its a first time occurrence).
I only have little dachshunds at the mo, but they are both aggressive over food, the boy more - he has drawn my blood a few times (I shouldn't tease him really, but we is both boys lol). So I give him grub when he is away from any public and tell people not to play with his grub or bone. But what would happen if someone fed him food on our campsite?
Bring back dog licenses - and for certain breeds, check the owners.
When you put into perspective how many sheep you would have to sell to match the profit from a pedigree 'dangerous' dog litter. Then look at the legislation and checks between the two? (I know one is destined for the food chain and one isn't but, I dont think you should be able to still in this day 'buy a dog as a christmas present'- , more control is needed)