Not by her parents, but by her older sister. My wife-to-be and I frequently snuggled on a couch in the family room, watching TV. Since I'm significantly taller than she is, I'd lay behind her (good reason, right?

). We'd usually have a blanket over us as it was chilly in the basement family room, so not much would show.
One night, the future SIL came downstairs to tell us something she'd seen on the TV. We heard her coming down the stairs, so I hurriedly pulled out and pulled up my shorts. The SIL sat down on a couch opposite us and chatted for about ten minutes, then went back upstairs. Didn't think much of it, so my GF and I resumed where we'd left off.
It wasn't until we were done and started getting dressed that my GF realized her bra had been sitting on the floor, in plain sight under the front of the couch all the time the SIL was there...
I figured that my GF had been a bit wild earlier on and had had a bad time with a boyfriend who knocked her up, then dumped her after she'd been forced by her parents to have an abortion. I'm a pretty quiet, conservative type, whom they and the SIL liked a lot more than her previous beau. So, I think they turned a blind eye to our activities.
They were right, too -- the Mrs. and I've been married almost 38 years, and we've never even had a serious fight.
F