My 2 cents...
There are some belligerent, repeat offenders out there, but from the sound of the OP here this sounds to me more like a person who is just clueless. For this, I would have just asked them nicely to "please give us some space".
repeat offender I wouldn't hesitate to call animal control.
I like to periodically test my dog's obedience, so I'll open up the back of my mini van with the dog inside and walk away. The dog has been trained to stay there until released, no matter who or what walks by. That being said, I did this in a park parking lot the other day, and a lady with a smallish doodle mix of some sort came walking by with her out-of-control dog (of course on one of those retractable leash monstrosities!).
They were parked 2 spaces from my car, and my dog sat there and let them walk by no problem... The little doodle dog kept pulling toward my car though, and reading the lady I knew I'd better move back closer LOL! Sure enough, after maybe 30 seconds of strong pulling she relented and decided that having this little dog come up to MY car for a meet-and-greet would be a good thing...after all, that's what precious wanted LOL!
Fortunately I was able to body block her dog about 4 feet out...my dog didn't move. The lady was quite upset though, with me for being so rude LOL!
I tried to explain to her about possesiveness over territory (the car) but I'm pretty sure my words landed on deaf ears. Ah well, at least her dog was able to go home with his face intact, and we didn't have to spend hours explaining why her dog was so terribly disfigured [IMG class=inlineimg]/forum/images/Germanshepherds_2016/smilies/tango_face_devil.png[/IMG]
OP, try to relax and calm yourself a bit out in public...your dog will definitely pick up on and react to your frustration and tension! Clueless people just need gentle guidance, they typically mean no harm...