It really depends on the person but I gotta agree with all those that say that it can be playing with fire. It can make old behavioural patterns connected with drinking flare up again, it tastes like real beer, it feels like drinking real beer...and alas, we humans are creatures whose brains work on memorized behavoiur, both conscious and unconscious.
I gotta admit, in the last 7 months I did drink a bottle of non-alcoholic beer on 2 occasions, and although it didn't trigger anything I have stopped drinking it. I didn't want to make it slowly become a habit, and then maybe lead to other things. Also, once I was drinking beer for the taste (I thougt the na beer would go good with some meals) and not for getting drunk, I realized that I didn't even like the taste.