My OH carries a big stick (I don't only because I can't juggle dogs, treats poo bags and a stick!) he is convinced it is more of a deterrent for other owners - not their dogs
As I am so much of a wuss now when I take the dogs after a scare, I have learnt how to shout
very very loudly, at the owners 'come and get your dog' repeatedly until they fetch it!!
I haven't got a problem with dogs coming over to play even if they bounce all over Harry he can sort that out himself and usually does
but after all the problems I have had with Ben over the years because of his reactive behaviour due to fear I just do not want dogs bouncing on him as he gets defensive, aggressive and fearful and after the dog has flounced off I still have a badly shaken Ben who is then quiet and reactive for a day or so at home, and I don't see why he should have to go through that when he is happy minding his own business on a walk, he just potters and does his own thing.
I've found if its just play another dog wants he will soon see Harry is up for a game and leave Ben alone, but if another dog is spoiling for some trouble then they head for Ben for some reason.