@MasterKingJC:
Yeah, they do. If someone put seastone on Luffy and shot him, it would still bounce back, because Luffy is always rubber.
EDIT: @Maki707 It still weakens them, but it's only touching their wrists.
Except, evidentally, when BB is touching him, seems to be the consensus we've reached on this thread… which means if BB held Luffy down, a crewmate could shoot and kill him, etc. Very dangerous foe for Luffy, who depends primarily on physical contact in his battles--and like I suggested, perhaps his battle with Magellan, another foe he was unable to touch, may have given him some worthwhile preparation for the coming battle with BB.
@Muda:
From what I've seen so far, Luffy's the only person whose DF is passive, meaning it's always active. Like you said, he doesn't activate himself to become rubber; he essentially IS rubber… I can't think of anyone else whose DF powers are passive as well; everyone I can think of has to activate their DFs in some fashion or another. Logias, on the other hand, I'm not sure if they're passive or not; ...
Buggy might be passive; The only way we can truly check though is to throw him into the sea, or throw some cuffs on him, and see if we can cut him in pieces with no harm done. Yeah?
EDIT: Just saw Alvida; Yeah, she might be passive too. If I remember correctly, her body's always slippery, no? If not, then nevermind.
Oda also said that when tossed into water, Chopper remains in the middle state he spends the majority of his time in, so that seems to be the default/passive part of his power, maybe? Even in full reindeer form he can speak and understand human speech… Just sayin' there's more to this than what we covered already.
@Don:
Yup thats right.
BB is able to "suck out" with his hand the effect the DF gives a user as long as he has contact with him..making the DF-user again a normal person out of flesh and bones for the timeperiod he can "suck" him with his dark vortex-technique(even when this technique might just be the one who pulls the user towards him and the actual technique to suck out the DF-power is like Crocodiles, who is able to suck with his one hand the water out of everything) {followed by interesting ideas about the workings of d/fs in water/against kairoseki–thank you}
(so he is able to hit Logia-users, cause they have no longer then the ability to turn into their element.)
So the question is, is BB's power passive–i.e. anyone touching him or being touched by him is subject to the effects of his d/f, or does he need to "turn it on" like Croc? On the one page you quoted, where he uses his power against Ace, he is shown saying the name of the attack, so it would appear he needs to consciously "turn it on," but that's a very limited reference to go on for making future predictions.
@Muda:
Seastone emits the power of the sea; that's the whole premise behind the stuff, so how would it do something that the sea itself couldn't do?
I'm still under the impression that the sea (and thus, seastone) weakens you from using your powers. So, since Luffy's always rubber (passively), he'll be weakened/lethargic when in cuffs but it doesn't neutralize his DF; Robin, who's not ALWAYS sprouting limbs, etc., (and thus, has to activate her powers) will not be able to do so with cuffs on, as we've seen.
EDIT: what access said…
This explanation, that several people have offered in various forms, actually makes the most sense to me, and finally I understand why Luffy gets so weak and tired where other D/F users just seem to lose their abilities. Thank you everyone. Very interesting discussion! I'm so looking forward to seeing what BB's power will be like as we continue on.