A woman needs to know that you'll have her back and aren't going to force her to make every move.
And if a person thinks they can tell that by the way they have been asked out, they probably deserve every jerk they get
Also gender roles. Old, overused, unnecessary and probably unhealthy, too.
And if I asked someone out by saying "So, are you interested in me?" I'd hope that they'd reject my sorry ass, too--for refusing to step out on a limb, just once, to ask somebody out. I say "a woman needs" because I'm speaking from my perspective to a man who is interested in women. It's just as applicable in the other direction.
That said, yes, I do think one can tell things from the manner in which someone asks one out. When someone says "Hey, girl in the pink shirt, do you want to go to homecoming?" and then stumbles along to "Oh, uh, what's your name?" I tend to think that they're more interested in my figure than my personality. When someone you see every day won't talk about sensitive topics or be particularly kind to you, save by email, I tend to think they're a coward who hides when the going gets tough. When someone with a strong interest in game theory tries to put you at an informational disadvantage... well, once again, I smell a rat.
I'm not saying that men need to do the asking. I'm saying that if you're going to try to catch someone, then
do it. No need for trumpets and overwrought statements of affection. Just get 'er done and have at it.