@HikaruYami:
The mermaids actually like sanji and his ridiculous pervert-power. That bothers me a lot more than the fact that hyper-innocent Luffy gets to bounce on giant titties.
It's easy to see why they like him: he's an excellent swimmer, and a lovesick goofball who would do absolutely anything they asked, and (even though he says a lot of perverted stuff) who has not made any attempts to cop a feel or anything.
All of the times that he's had his face plastered against the boobs of a lady were times that either the lady herself caused that to happen, or some freak act of fate caused him to fall against her, or vice versa.
Have we ever seen him kiss a woman? he's hugged a few and chased a few, but that's the extent of his passion so far. So except for being aware of the attraction of women and having a strong opinion about that attraction, he's actually almost as innocent as Luffy. Think of it this way: Sanji has already hit puberty and got the lecture about the birds and the bees; Luffy hasn't.
I am quite certain that it must have some other interesting (potentially miraculous) properties.
Maybe the light comes through it so easily because it is hollow, and because it is hollow, it is possible to move through it to get to the Holy Land without being discovered? Yes, I know, that's extremely far-fetched – but it was just a crazy thought about some potential "other properties" possibilities.
@Mr.:
I already have a list prepared for such a harem:
Dirt Monkey Al will love that!
Wait a minute … "Miss Universe"?
Who is she?
The wife of Wapol or something?
@NANLIT:
I've moved the Shanks' arm/strength talk to the "Questions That Don't Deserve Their Own Thread" thread.
Thanks NANLIT.
The thread's in good hands now. :)