We bought a pair of "cheapies" for our recent trip, and they were fantastic. We heard other people a couple of times, but that was it!
they were so nice to have. EVen though we never split up very much, it was great to have even if my DH wanted to get a drink or shop while I took the girls for a "Potty break"!
Several times we went in different directions in places like Innoventions, but we were never more than a call away from each other.
One afternoon I forgot to bring them, and I thought I'd lose my mind, trying to keep track of my DH!!! LOL