Just a recall of the past even though it may of not been all that great!
I remember back in the day when we used to get spammed by gil sellers with there tells to go somewhere out of character and out of the game, they would direct folks to it in there bad man tells, spamming everyone on the sever but this type of thing happening in a logical different way could probably use a spam filter like they did in the old days to block it's occurrences from continually happening inside the unity chat. it be something like /uchataid, /uchatspamblock, etc. and so on and so forth! LOL!! hope its a simple solution and a great idea! ;)