To the commenter who asked, "Why didn't you call 911?"
Because last year when exactly the same thing happened on West 1oth Avenue (An infant in a van with the sliding door open and no sign anywhere of a parent...) and I immediately called the police, here's what happened.
Before the police arrived about 10 minutes later, the "mother" emerged from a tanning spa with a fashion mag in her hands. I asked her if this was her car and child. She said they were. I told her the police were on their way. She thought I was a public nuisance. She laughed at me.
When the police arrived, one officer stood by me. The other stood with the "mother," and the two of them - the "mother" and the police officer laughed a lot.
I asked them what was so impossibly funny.
A month before this incident, a friend who used to own a plant store down the street had precisely the identical experience - baby in car, no parent, police, much amusement...
Apparently there is something inherently hilarious about irresponsible senseless parents who are born to shop and tan and the crazy lunatic old men who accuse them of reckless child abandonment.
Watch for the new ABC reality show based on this growing trend called "Lose Your Kid, Find a Grumpy Old Man." The early returns from the focus groups say it's a smash run-away winner.