Ignoring the name tags is part of RP. It is bothersome when some OOC info is used as if acquired IC. Not only through the name or guild tags but also with /tell. For example:
/<name> tells you "I need help, come right now!"
Duh! how would I know this is happening? Not everyone can RP telepathy nor should they. Why not try something a little bit more IC for this kind of message like: [a groffle brings you a note], /me whistles, etc... What you learn OOC or through OOC ways (like tabs, /guild, /tell, [ ] or forum threads) has to find an IC way to reach your character. Otherwise, how could they find out? Most ignore this side of RP and that leads to situations in which the characters can't explain how they got there to begin with. "Funny coincidence we meet here in the middle of nowhere"... this could be avoided with a little [you receive a note: "Meet me <place>. <Name>"].
Ok, maybe it's an honest mistake to come and say "Hi <name>!" to someone we've never met before but if they try to RP that they don't know you and even tell you a false name don't go "But your name is <another name>!". Play along, how could your character know he's not being told the truth? (unless you come up with something IC to explain this knowledge, do keep the RP going).