It is common sense for you because you happen to be used to it this particular way. The truth is there is no standard for it one way or another. Typically games, such as Bannerlord does with the clan tag, will have a separate column for it so it wouldn't even be in the name in the first place.
That said in general if there is no explicit rule against something, it shouldn't be punishable with suspensions or worse at all. Simply because no rules are broken to begin with. People agree to a written set of rules and if it's not in there how are they to know? If it's a common unwritten consensus something should be done a certain way at most it should warrant a warning unless maybe it is a repeat offence. It's silly and unwarranted because again, how are they to know if they are new players?