There is more chance that Danielle was abducted by UFO aliens, who after all can go through walls, roofs, etc...than that DW, who at 50 and formerly a bit paunchy, could have floated like a butterfly, stung like a bee, and buzzed right upstairs where Damon was having sex with someone, or wasn't, past the VD love nest, and grabbed Danielle without anyone hearing him or her or being the wiser. And no evidence-- not a scrap, not a shred.
In fact, there is more chance that Danielle was taken by space aliens, than that anyone at all entered the VD home without permission and took her.
Why don't they at least make it POSSIBLE by saying she walked out and DW took her from the roadside or the park.