On Xbox Live it does not display even if you type "Linux"

By selecting "Gamer Motto" from "Edit Gamer Profile" of "Xbox LIVE Profile"Can display the current mottoAlthough it is reasonable, it seems that I can not enter "Linux" for some reason. Correctly, if you enter Linux, it means you get angry with a message saying that it can not be accepted.

The movie which recorded the state that it can not be entered actually, and the reason for it from the following.
Movie shot of how this can not be actually entered
YouTube - Microsoft bans term linux in XBOX live


There are other words that can not be entered, and it seems that there are times when it is set not to display in trademark relation besides so-called "unpleasant words".

Xbox Live NG word "Linux" "Unix"

>, Are they truly engaged in trademarks?

It seems like that. I do not know how reliable it is because it is not clearly stated who is speaking, but in the following article it is mentioned that it is a matter of trademark as an answer heard by telephone.

Why you really can not use 'Linux' as a screen name on the Xbox 360[Linux-watch.com]

Although it seems that there are things that many pass through other trademarks, it can be said that it is a conclusion that we arrived at the end of various circumstances, consideration and consideration ......