Happened to me in MAD recently. They'll put cargo on until the next pallet puts us over max gross wt. Then they'll know how many pounds of non-revs they can put on to take it right up to max. So, often a few get on, but no one knows until just before they close it up. The Capt has almost no control, in case you're wondering. There was one a few years ago that refused to leave unless her husband got on, so they bumped cargo. Most of us can't get away with that.