Saw two kids alone in a parked car. I don't know what I should do.

I was on my lunch break at work, so I went out to grab a bite to eat at the local sandwich shop. When I was coming out, I saw a little boy waving to me, so I walked over and realized it was my 6 year old (second) cousin and his 2 month old sister. I was floored when I realized they were in the car by themselves, so I went to open his door; surely it would at least be locked? Nope!!!The car was running with the air conditioner on with the doors unlocked. I asked him what's going on? And he said his mom (my cousin's fiancee) is inside the coffee shop. So I asked if he was okay and he said yes - then I casually said "mommy left you alone huh?", and he said "oh this isn't the first time."I stayed with them chit chatting for at least 5 minutes until their mother came back and she's like "Oooh, they kept me talking in there! Thanks for waiting with them!" Really?!? They kept you talking in there!?I'm so upset, and I don't know what or if I should do anything with this information. There are so many bad scenarios that could have taken place. What if I were a bad guy and drove off in the car? What if he somehow got the car to maneuver? She's playing it off like it's "just because" she got caught up talking, but two young children should not be left in a car, PERIOD. It's illegal!What are your thoughts, fellow parents? Should I just let it go? Should I bring my concerns up to her, or someone else? via /r/Parenting http://ift.tt/28OdLvn