Why do these people get to have more children?

One of my issues with these losses over the past 6+ months has been why some people are allowed to have children (or more children) when they do such completely idiotic, mindless, stupid things. As a perfect example of this...here is something that happened to my MIL:

We went to our Godson's 3rd birthday party on Saturday at a place called Imagine That! - a children's museum with a whole slew of exhibits for children to play with (unfortunately, it does not look as nice as it sounds....the exhibits are very old and worn out now, and no one has made the effort to update/clean things up). But, I digress... Dh and I decided to take Chris home before the end of the party (we left at 12:30 pm - the party ended shortly after that) because he missed his nap for the party and he was BEAT! My MIL and FIL decided to stay past when we did... Here is where the story begins...

By 12:45 pm, we have having the heaviest rain we have had in at least 6 months... My IL's decide to leave since the party was breaking up anyway. My FIL headed out to get the car while my MIL waited in the lobby for him to swing the car around. As she was waiting, a woman pulled up in her brandy-new Volvo station wagon and helped her DS out of the car... My MIL opened the front door for her, thinking she was coming in with the boy. The woman brought her DS in and said to him, "Now, Adam, stay here and wait for Mommy to come back." She then looked at my MIL and said "Do you mind watching him a sec?" and off she went back to the car.

At this point, the little boy proceeded to inform my MIL that he was 3 years old, he lived in a really nice neighborhood, blah, blah, blah... He sounded like he is 7 years old!

My MIL spotted the woman coming back to the door, so she yet again held the door for this woman because she was carrying a baby carrier. The woman set the baby carrier down next to Adam and said "Now, Adam, watch your baby sister and wait for Mommy." She yet again asked my MIL to watch the both of them and headed out the door without waiting for an answer.

The little boy proceeded to tell my MIL that his little sister's name was Lydia and she was 3 months old...

As my MIL stood there in shock, she watched the woman pull off and park the car at the far end of the lot. After she parked, she pulled out all of her stuff and trekked back to the door. She briskly said, "Thanks" to my MIL and went into the museum with the kids.

Uh, WTF??? That security guy that Oprah has on every once in a while would have had a FIELD DAY with this one! My MIL could have been off and running with those 2 children by the time she came back after parking the car. Sure, my MIL looks like a nice lady and very trusting, but there are a LOT of people who look trusting and end up being far from it.

My two questions for this woman are: 1) if you were attending a party (which was clear she was), why couldn't she have had someone meet her at the door to help her? and 2) if there was no one she knew attending the party, why didn't she either wait for the rain to let up (which it did 10 minutes later) OR call the facility and ask if one of the staff people could help her? She let a complete stranger watch her DC, and she walked off without a care in the world. Maybe it's just me and my "mental state" right now...but am I the only one who sees that as completely wrong to do?

...And, may I add, I got looked at very strangely by one of the parents from another party at this place for actually correcting Christopher for doing something he should not have done... I swear, I am parenting in the wrong decade!

I was so disgusted after hearing this... Kids can be snatched off in a split second - I must be Hitler in the store when we go out! I really can't understand how someone could do that...