I'd say it's more that, while guys do rate on a ten point scale of hotness, they generally ignore these ratings in favor of the y/n option. Although of course there are definitely cases of maybe in there. The "... welllll... maybe in a few more drinks..." option.
Edit: in fact, I think I overheard someone mentioning they actually used such a system to rate attractiveness. So there's "sober", "six pack", and so on. Said comment then followed into "but I don't think even a 30 pack would be enough for her".