I personally find it ridiculous when waiters do not at least ask groups of four or more guys if they want separate checks in a restaurant. I'd certainly be fine if they didn't ask and did it anyway, but to present a full table of people a single check at the end of a meal is just dumb. It just serves to annoy everyone involved, especially since half the time they're going to make you go back and split it up anyway.
It wouldn't be a big deal if I could actually remember to ask when ordering, but it seems so absurd to me that the waiter would even consider a single check that it doesn't even come to mind most of the time. I'm more likely to remember if it's just one or two other people.