These things are always so bizarre you don’t know how to respond.
So you default to polite. That’s a mistake. But, happily, one you can retrain.
Politeness is a basic act of trust, which exposes you to those with ill intent. They actually often depend on this dynamic to strike.
NEVER TRUST STRANGE MEN UNTIL THEY HAVE EARNED IT OR YOU HAVE OBSERVED THEM LONG ENOUGH TO KNOW THEY MEAN NO HARM.
NEVER.
You owe strangers civility. Not politeness. They’re not exactly the same thing.
Civility says, “No, thanks. Good day,” while walking away.
Politeness stops, makes a fake show of looking in, and engaging somewhat. Politeness waits for a response, which could be an attack.
Next time something like this happens, do not engage. Keep moving. When they call out to you, say “No, thanks. Good day,” and keep moving.
Get their car details. Make, model, license, color. If you’ve got your phone, take a pic.
After they’ve driven off, find a corner spot, camp out a while and make sure they’re not doubling back and following you. If you see them again, call the police and request a neighborhood drive through. Tell them what happened and give them the details.
Train yourself and your kids for a default response of civility, not politeness.
Creepy people do not deserve politeness.