Strangest thing - is it possible for my fob/Prius to open my garage door?

EDIT: resolved, see post 4
----------

Here's what happened:

I just was getting home in my Prius, and pull up in my usual spot in front of the house. I get out, and as usual, since SKS is activated, push the rubber button on the door handle to lock the door. Fob is in my pocket as usual.

The car is in the street about 35 feet from the house. I walk halfway across the lawn, and the garage door starts to open. I do not have Homelink or anything, and haven't tried setting anything up differently in the recent past. I thought one of my parents was opening the door for me. I walk towards it, and it stops, about a quarter of the way up.

Confused, I backtrack a bit to go in the front door. The garage door is still sitting a quarter of the way open, not moving.

No one in the house was near a garage door opener, and I've never had one in my car, and never carry one with me.

I live in a neighborhood where nothing's doing - probably all the neighbors were sleeping, it's just separate houses in the suburbs. Is it possible my fob or the car opened the door, and then somehow sent out another frequency to stop it?

 

Thanks guys, indeed it wasn't the fob, but some other signal - from a garage door opener.

I just found one in my bag, which must've gotten hit twice when I was walking to the house. The real mystery now is how the hey it got there, since like I said, I never use it. A running theory is that my sister's cat, who we were recently catsitting, really enjoys throwing small objects off the table, and my bag often sits open nearby...