When we went to WDW in October, we had a communication device for our DD in her backpack (we were trialing it). It looks like a small tablet computer. The security people did usually ask what it was, but took our explanation. If they had wanted to know more, we didn't have any literature about it, but could have easily turned it on and demonstrated it.
I agree with the others that the security people may not show much interest in it, but it would be helpful to have a booklet or something to explain it.