Sadly, very often.
The other day I had two in a row bail before the first hole was over. In both instances, I'd dropped my approach within 3 feet. I waited, knowing that I'd either get a 'nice shot' and the game would continue, or I'd sit forever waiting for their disconnect to register. Sometimes it's best to get it over with early. It's really galling for someone who's losing to leave on the next to last hole.
Country clubs are a good way to avoid this, but many have members who concentrate on the solo tourneys. Try to find one where the folk regularly play multi.