I think in most circles, if you had a wedding of decent size, it would be weird and Twilight Zone-ish if absolutely no one gave you a present. Because generally, people do. So I think there's a difference between "expecting" people as a whole to do what they usually do under normal circumstances, and "expecting" as in "counting on down to every last detail."
But I think it can be a fine line, or maybe a slippery slope. I've never heard anyone suggest that it's rude to make arrangements for your wedding gifts to be transported from the venue to somewhere safe, because it's rude to assume that you're going to get any gifts. That's just being sensible and pragmatic.
And from there, one step at a time, you're reasoning that you won't have to pay for THIS because someone will buy it for you, and you won't have to pay for THAT, and "I estimate my extended family will give me $X total at the wedding, which we can put towards Y expense..." And that's a little dangerous, but to some people it can seem, again, just being pragmatic and planning ahead, and also enjoying the anticipation of getting gifts, which is not in itself bad I think.
And then the slope slips a little more, and you're standing on the other side going, "Why did Uncle Bob give me a Precious Moments figure that I didn't want?! I was counting on at least $200 cash from him, that's what he always gives!! How are we going to get the cabinets redone now?!" Which is rude.
Not that everyone has to go through the whole process, of course, but I think it's very easy for some people, who are otherwise polite, to slip further and further without realizing how far they've gone.