I have used my free bag tag once. The main oddity I had was that my bag had a new label slapped *over* the screen when I had a misconnection. It took a bit of effort to get the glue off.
I guess that is one way to reprogram these things. I understand that they can't leave the original flight info on the tag, but perhaps giving AS staff with their ubiquitous tablets the ability to reprogram them if needed would be better than pasting a label over it, and especially one that can't easily be removed without leaving residue behind.