I was reading a semi annual pamphlet that is put out by our local spca and it was listing some new and some not so known by-laws for our city.
It brought up the fact that dogs tied up outside of stores and such are considered to be "at large" and are treated as such if they do anything....whether it be actually biting someone, or jumping up and scaring someone. Here it could mean up to a $1000 fine.

I agree with everyone and suggest not tying him up outside unattended anymore. You may trust your dog, but you cannot trust the strangers walking by your dog.