I'm quite sure the RCCL rep was wrong given that you both have been on the ship. I agree its pathetic that they would just guess on something like this rather than apologizing and explaining they don't know the answer and have no real way of finding out.
Anyway... I have been scouring the web trying to find a detaied picture of the balcony door so that I can assess if there is anything I can bring with me to create a makeshift childproof lock. We have sliding glass doors at home and they are infamous for being able to unlock by jiggling. In order to prevent burglars from doing this from the outside, we have a piece of wood in the track of the door preventing it from sliding open, locked or not. Does anyone reading this have a detailed picture (or recollection) of the door such that you can determine if the door that moves is on the inside or outside? If it slides open on the inside, I think I could bring a shower rod or something similar which is designed to be flexible in width and stay open above the reach of the kids. If the door slides open on the outside (opposite of traditional home design), then I could put the same rod on the outside. The only catch here is I would then need an alternate way to get back inside.
This leads me to my last question: If we get connecting balcony rooms on the RCCL Liberty of the Seas, can we have the divider between the two balconies removed so that I can lock one balcony door from the outside and then re-enter the ship through the other balcony door?
Thanks once again for your responses to what I will admit is a very anal line of questioning.