I've gone through and read all the posts and come to one conclusion: Most people here think that UM's are going to be crying, whining, and peeing their pants the entire flight.
Now, I don't plan on ever having children. But being on my fair share of flights, I've noticed that all those crying and whining kids are with their parents. Now, as far as I know, parents wouldn't send their children on solo flights if they're prone to fright or temper tantrums. Being a kid and flying alone is known to the child as a big responsibility! So I can say that at least 98% of the time, the UM won't be crying for their mommy or puking in a bag. Because you know what? They're actually kinda mature for their age.
That being said, I don't see what the huge fuss is to be seated next to a UM if you're male or female. I think it's quite silly that men are singled-out here as 'predators' because there really is no space on a plane to even BE a child 'predator'. But all this disgust of the thought of being sat next to a UM? Really, chatting with a child for 5 minutes might actually be kind of fun and/or cute. Considering the fact that children also have "Do not talk to strangers!" drilled into their heads, and with all the fun gadgets nowadays, one would probably have to do nothing to keep the kid entertained in any way.
Personally, I'd rather have a UM sitting next to me than some drunk/smelly/rude person. And goodness knows, there are more of THOSE people on flights than UMs.