Just looking for reviews of this bag, and I read like one person say that this sling bag can fall off or comes undone? That would be a very bad thing for my UBMBP. So any takes on this? I would have it in a Sleeve then the backpack. Any reviews would be great. Or any ideas for a bag around that price. I'm in an air port at least once a month so "flight friendly" would be great. I need to protect my new baby.