@ThatGuyThere A lot of people do, actually. I know a lot of folks who don't want to exclude anyone from the ceremony, so there's not really an invitation sent out for the ceremony at all -- it's just 'everybody in the family and friends group knows about it and is welcome to show up if they want' but they don't have the $$$$$ to pay for a ton of people to attend a reception, so the only actual invites that go out are for that. That shit's expensive. Average per guest in this area, for instance, is $75+ per guest, including children for a small, not terribly fancy sort of thing, unless you're doing something like a casual buffet at your house.
There's a reason I did the justice of the peace thing to handle the actual wedding with just my husband's mother and my parents there, and that we're saving up for an additional 2-3 years to have a small reception for just the closest of the close friends and relatives.