Depends who it is you see. Is it some A++, super-cool person that enhances your image? Then yes, by all means. Where applicable, shake hands / fist bump / do the gangsta-shoulder mash, to show your date you are connected.
OTOH, if you see some shleppy nudnik headed your way, freeze, and say “Woah, I think I left the car door unlocked, do a 180, and get some distance between you and your obstacle (and hope your date did not catch on.. which they probably did, but will still give you credit for quick thinking)
One more thing. If the on coming problem is a kid brother or cousin, watch for a set up, as there may be someone directly behind you when you do the about face.
(Gee, guys, you really need to lighten up here. Its a date, for heaven’s sake. Relax a little!)