In my opinion. The unit us made for friends.
what's the point of it , if you can use /clearchat ?
I've never join to unit, but it's really helpful cuz many harming it.
I think that this would delete the conversation between him and his friends. In fmsg or sms. (Not talking about J)
And max members are 8 so if you got annoyed from friends and u don't have that fun spirit you better leave the unit and really a kick from the server you better don't join a random units then.