I'd been contemplating the Deer Event scenario already, but there's still no garden damage and I think they've stopped coming. We've staged a few Coyote Events when we hear the pack passing in the fields, and that may have scared off the deer (it's been less efficacious with the coyotes, though they do choose the fields over the yard).
I'll try the yarn; thanks for the idea. I have plenty of trees for stringing it, no need for stapled wands in most places. I'm pretty sure I know where the holes are -- there are only a few spots where even a deer could get close enough to jump the fence -- we're that overgrown with brambles, etc. If I visually heighten the fence at those points (and at my gate), I think I'd lose the problem.
I suppose I'm glad I don't have moose, though if I did, I could just charge admission to see 'em and buy my food at the store!