You usually want to get to know the person before you date them so it's more likely that you will last. If you ask a random girl then it might turn out that you don't even like her. But it's not wrong.
i would only connect with acquaintances. random has too many built in skewy possibilities.. every time a gal pursued me (that i didnt know) it was for a "reason" that served her interest (even when not a professional) :)