@Greg:
Yes thanks dude, that's what I mean. We're not gonna see a knock-down drag-out battle between him and a woman.
I'm not sure if I agree with the 'good' reason for punching though. I'm a firm believer in the Chris Rock theory of female-male pugilistic relations. I'll never hit a woman, "but I'll shake the shit out of her."
Well, she did punch Vivi for a Good Reason, saving her from her own hysteria about sacrificing herself for everyone and what not, and in Alvida's case, I think that Luffy had some mercy and sent her flying away with his weakest atack instead of pummeling her to almost death like he had done with the other villains, so you could say that in both cases he just knocked some sense in their heads before they got into more ugly situations. I mean, Vivi would have gone to the extreme to save her country without realizing the flaws of her plans and Alvida would have surely died at the hands of other Pirates if she had not meet Buggy and formed a solid alliance of sorts…
Anyways, I think that Luffy actually fears his mother to the point where he doesn't even dare to mention her, just like he did with Garp before meeting Aokiji. Besides, it would kinda make sense that Ace told Luffy about her, assuming that Ace doesn't even know Dragon at all.....
But speaking of Ace...
What do you think that will be Dragon's reaction at Ace's defeat at the hands of Blackbeard? So far, I think that Ace's admiration for Whitebeard comes from the fact that he found a "father" rather than admiring him for being the strongest old geezer of the world, but who knows, it's just weird that Dragon is "waiting" for Luffy when Ace was already on the Grand Line ....