Good idea, not even sure the vinegar would be necessary. Water alone will usually throw them off.
Some friends used bitter apple to train their dogs. It could be used to fill a water pistol and dogs seem to really hate it.
The problem with pepper spray is that if you are upwind when you spray the stuff, you have just pepper sprayed yourself.
I've been hit with pepper spray. (military uses it and tear gas to show us our gas masks work. So they claim). I'd rather deal with the dog.
re-cur-sion ri'-ker-shen n: see recursion