if it was up to me (ha!), dogs would be muzzled by law, with some latitude to allow for the above circumstances.
though I would also make it compulsory for dog owners to insure their pets in a third party kind of way…your car is insured because even though you put the handbrake on theres no guarantee that it would not roll down the hill, etc.
likewise, you take your dogs muzzle off to feed it, theres no guarantee that it would not bound off somewhere. so muzzling and third party insurance go hand in hand.
if you felt confident that your dog could be unmuzzled at said pub, the insurance would handsomely compensate anyone inconvenienced by said pooch.
though as for dogs playing ‘fetch’, i guess that its unrestrained dogs behaving in this manner that are the bane of most cyclists…one mans pleasure can be anothers ‘negative externality’.
plus, muzzled dogs represent a vast reduction in unnecessary barking!