I don't put anything in my mouth that has alcohol in it--nonalcoholic beer or cider, cold meds, herbal tinctures, etc. would a couple of drops of "rescue remedy" send me on a bender? Well, probably not. But for me, it's a zero tolerance thing. I know how my sneaky alcoholic voice works. If a nonalcoholic beer with 0.5% alcohol is ok, then why wouldn't a little taste of champagne be ok? Surely it's fine to put a little splash of beer into some Sprite to make a nice refreshing shandy drink. Then it's back to full on alcoholic drinking in no time. That's how it would be for me, anyway. So While it's unlikely that a teeny amount of alcohol would really do any harm, why risk it?
PS once I accidentally drank a swig of nonalcoholic cider that I had purchased thinking it was totally without alcohol, like a fizzy juice rink. Immediately I could tell it was the kind that was 0.5% alcohol. I spit it out in the sink and rinsed my mouth out with water. Haha a little paranoid I think. But I have to treat alcohol like the poison that it is to me.