Nope that's a bit over the top of any child I seen

They wet their pants anyway so who'd notice?

I agree 100% with Tex and Tova: keep your hands off my kids!
If my children weren't behaving I'd wanna know about it, and I've never had a problem with people saying something to my kids, as long as they were respectful in doing so.

Usually it was adults being rude to my kids! and I wanted to swat the adults!
A couple of times adults tried to pick on my kids and then they had me to deal with. That's when their fun ended and they had to deal with someone their own size.

BTW, 8 and 9 year olds SHOULD know full well better than to act like that in a library. (And who the hell would leave them there ALONE?)

If you tell kids to not run around in a playground, that would be something, but a library???? THeres nothing wrong with it moreover, kids will be kids and thats how they will behave.
I personally think there was nothing wrong with what you did,I would do the same.

BTW, 8 and 9 year olds SHOULD know full well better than to act like that in a library. (And who the hell would leave them there ALONE?)

See, and that's one of the things that concerns me about our society. We demand that a parent feeding their children rice and beans to save a few bucks is somehow harming their child, but we turn a blind eye to parents who drop their kids off at the library door then disappear for half a day (or, worse, just shrug the kids off and send them on the way to the library because you don't DARE interrupt when Rosie's ranting on "the View". The latter children might not have all of the material luxuries of some of the others in society, but the former children more likely than not will discover a lot of wrong choices before they discover the right ones because there was no adult present to guide them.

You politely asked them to settle down. That is not disciplining a child. I would never want someone trying to discipline my children, but I don't have any problem with treating them with respect and politely asking them to stop doing something that you don't feel is appropriate. I had a neighbor who felt it was his place in life to yell at my children because they were making too much noise playing outside. I berated him, because all he had to do was treat them like any other person as politely ask them to quiet down and they would have. I don't understand why people think that children deserve less respect than an adult counterpart. If you don't treat children with respect, than how do you expect them to treat others with respect?