I'm an AMA member because I belong to an AMA chartered club.
Times have changed; there was a time we would have liked to have recovered lost models...
At the risk of having fingers pointed my way, I honestly believe I share the silent thoughts of a majority that would not want to share a unique identifier on their models.
Last time I had a fly-a-way was due to stupidity assisted by impairment and flying in a place I shouldn't have been; I was tempting fate by flying into and out of a low cloud layer. Now-a-days, genuine fly-a-ways are very unlikely but I set model failsafe to crash as expeditiously as possible like I'm sure many do anyway. I certainly wouldn't want to be bothered by the worry of a lost fly-a-way even if it landed unscathed. Would you?
Why would you want anyone - say a local farmer to discover your model in his field then report this find to FAA authorities and have them show up at your door because of a unique identifier?