the reason is simple people who dont care if low lvl's who havent earned the right to be there let them port. i bet you see more low lvl's that you dont know than you do. i think imo that low lvl's will always go into higher lvl worlds.
Yeah, on my life wizard, I was having a level 23 myth guy following me around sometimes and I didn't mind at all. I hope that the other people didn't get annoyed with me though o: