Oh come on... we see it all the time! Or at least I did. You'll be invited over to somebody elses house... and like the parents are all oblivious to what their kids are doing. I'd always be that guy who shoots out his hand at the last second and prevents their toddler kid from impaling their temple on the sharp corner of a coffee table. Stuff like that. Long story shorter, I'm just saying, in my opinion, if you've got 6 adults, together with 4 kids... and this is me presuming toddler type ages... if you let them get far enough away from you that it made a mountain lion feel confident he could snatch one and get away with it? Sorry dude, but you're failing. Again, just my opinion on it.
EDIT: Also, just for some perspective, I have a small dog +/- 23 Lbs, and a very small dog < 5 Lbs. So I'm very used to being constantly vigilent when out and about with them. Especially the little one because it adds the additional threat of raptors swooping in, into the mix. So ya have to also "keep an eye to the sky" as well. And yes... she does sometimes attract their attention and they start trying to follow ya, hanging back looking for opportunities.