The support don't typically do that, the verification is automated, just like you clicking "process checkout" or whatever, they don't verify, they basically just emulate what you are doing by clicking submit, thereby relying on the card company to be updated right away.
It's all about fraud man... if there weren't crooks out there, we wouldn't have politicians! Oops, wait, I meant to say, if there weren't crooks out there, we wouldn't need all these checks and balances that sometimes have issues for people purchasing items.
I agree, it sucks, but it would suck worse if some clown got ahold of my card(without me knowing) and used it to ship a thousand dollar computer somewhere.