Only because of the streamers (b0aty) it is common knowledge he has access to other peoples accounts, and they have to his, they aren't exactly going to ban someone who attracts a lot of players to runescape. So they had to bend the rule, it's quite sad actually.
But yeah it's not bannable - UNLESS! It is abused to gain ranks on the highscore, - this shouldn't be an issue as even if you do none of you are gonna reach the top page on rs.