How did I accidentally find myself in a carpark known for dogging and swingers?

We had both old and young couples parked next to us obnoxiously staring into our car and waving at us. I didn't really think much of it, and smiled at them. That was until we saw a different couple having sex in their car.
Only then did it register that these other supposed friendly couples weren't just being friendly, they were signalling to us for a good time😭 lmao.