The %1 thing is there for the purpose of welcome messages and events which say your player's name (eg. RPs). If anyone actually takes the use of %1 to heart then grow up.
I was running a server about a week ago and started minigame-eventing messages with players names. Even when I used the age old "Badspot has connected" thing there was 'HAXXXX', 'someone's hacking' etc. Even after I SAID it was me paranoia was still rife.
Honestly. If you didn't say something that appears after your name just say so. Everyone who has any mental capacity knows how it is done and will know instantly that you didn't say it and will laugh at you because it's funny. (Of course, if you DID say something don't lie).