I know what you mean.
With my older dog Jess my Grandad takes a wooden walking stick (he dosnt need it to walk) with him just incase another dog tries to attack her.
He wouldnt wack the other dog over the head with it lol! but just to get them to back off if they were being aggresive.
There used to be a Boxer dog which lived 3 doors up from us, One day I was walking down the street with Jess and the Boxer just came bursting out of the house and ran straight for her it bit all her face and her side.
Poor thing got such a fright she jumped right into my arms and I had to catch her.
I was kicking the thing like crazy as it jumped up at me to get her and all the time its owner was watching!
Bloody horrible thing it was it used to kill sheep in the area and everything... Jess was so scared every time she was out and saw it but would bark and growl like a tuff cookie if she was safe in the house and he walked past
The boxer is dead now though... its not a good thing but atleast it cant hurt any more animals.