I wonder if this would work on the kids...Cheaper than a fence, and I wouldn't have to get off the couch to keep an eye on them.

cheaper than tranquilizers too

Has anyone actually used one of these "systems" with success?

^ my next door neighbor has one, don't know what brand but it seems to work fine... except a few days after the collar battery wore down the dog figured that out before the owner did. They were having batteries delivered on a schedule (monthly??) which reminded them to change the battery and didn't notice that one hadn't come on time. Keep a spare battery and change it on a calendar schedule not just when it shows up in the mail.