I don't know, if they just kept it in their room and it was mainly for dad to call-so you do not have to deal with him-that actually sounds really cool.....but other then that-where i live my kids were never out of my sight unless they were at school,until at least 8 or 9 years old when they could ride their bike around the block in the evenings...but I was usually outside then too...when is a 5 or 6 year old away from its parent, or another adult watching them? My 15 year old uses mine sometimes when she is at a friends house, or at an event. I have not bought her one yet.
Mi kid is 16 and has no cell phone...if he needs one he can use mine or my wife's.
I think it's important to differentiate between cell phones and the emergency kids' models. The kids models have all sorts of restrictions and controls on them - e.g. kids can only phone a few designated numbers and emergency numbers. It's not the same as having a standard cell phone that they can ring people on, all day long, with no specific need. I wouldn't like my young child having a standard cell phone (I feel weird saying that, we call them "mobile phones") - but I would INSIST they have on of the kids' models.
I sometimes hate being attached to and relying on mobile contact. The more technology we rely on and depend on the lazier we tend to get(as an individual and a society). Personally I would not give a 5 year old that burden. Give the kids their childhood without todays strings attached. Do you really NEED GPS for a child? Why not put a micro chip in them like we do for lost dogs and such? I agree technology is great and I enjoy seeing the latest and greatest, but to introduce these to a child is unfair, unnecessary, and in some ways it is doing them an injustice. What are you going to use GPS for? Seems completely unnecessary. I had no problem learning responsibility without a CELL PHONE (I don't think I learned it at 5 yrs old though) and as long as I was being looked out for by a mature responsible adult. As for not having to wait for grandma or papa to call mom......Don't they need to learn patience, and respect for elders? How many times is there an emergency when a cell phone is the only means of communication? Wait until they are teenagers before introducing them to this burden. It sounds like you feel guilty because you are so busy and you want to compensate for it by giving innocent 5 and 6 year olds a cell phone. It seems that you already have your mind made up but you asked for opinions, so, although I am not a parent, I think it is a bad idea.