I've checked interface and I couldn't find anything relating to tips or quoting anything the actual tips in game say...
I don't think they are changeable.. Maybe add them to Quest log if your not using Quests ?
Else you could use "-tips" then display a random tip to the user?
Interface would be the only place they would be, so they are hard coded into the the game and you need to use an alternate (such as above)
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.