[HR] bbcode, is this OK?

[TigerC10]

There's nothing wrong with doing it that way, the only issue you have is that it won't be added to the bbcode help page listing.

As far as limiting who can use it, I don't think that there's any reason to limit that bbcode. The way you would limit it is at the beginning like bbcode_parse_start, you would match/replace with a blank.