Yep, I've seen that kind of thing happen before. In fact, it's happened fairly recently to me.
My youngest DC goes to a nursery in a fairly middle class area. Think lots of nouveau riche parents owning plumbing companies and roofing companies, driving big white 4 by 4s with their surname as a personalised numberplate. DC3 has been attending for a term now and at the beginning very few parents spoke to me, or I'd just get a very dismissive 'hi' if I tried to make conversation with some of them.
I generally walk to nursery as it's very nearby, but recently with the weather being so bad I've driven there. It just so happens that my car is a brand new convertible. The first time I turned up by car, I could visibly see that I was somehow more welcomed into the group of parents, and that they seemed to think I was one of them! One parent actually saw me pull up, got out of her car and waited by my car for me to get out, commented on what a lovely car I have, and asked if it was mine! Two days previously I'd held the door open at nursery for her and said hello and she'd marched through, without a hello or a thank you, and any attempts to chat to her had been rebuffed.
I can't say I am bothered one way or the other about having 'friends' at the nursery pick up, but I have noticed that since I've travelled by car I do get spoken to, and included a lot more in things. Co-incidence? Perhaps, but it all seems quite strange.