Why not mention the names now? It is well known that this behaviour is far from acceptable on any airsoft field, anywhere.
If two players want to slug it out on the field, fine, whatever.. it's immature and not appropriate.. but in that case I could see the course of action you took.
Deliberately firing an airsoft gun at someone, point blank, in a safe zone, is an extreme hazard to everyone else. At that point that player intentionally physically endangered other people. In my books that should be grounds right there for a ban. There's no excuse whatsoever for behaviour like that.
"Someone in a Prius tried to race me at a stop sign the other day. I couldn't believe it. I had him for the first 100 feet or so but I can only walk so fast."