It's not unheard of, it's just largely impractical. The hotels are something like a 45 minute drive away, and there aren't many of them.
Additionally, this year's Sasquatch ticket comes with your camping pass included in the price. So, you buy Sasquatch admission, you buy camping. There have been mixed reviews with a tendency toward the positive.
Also, camping is "part of the experience" and blah blah blah. I'll let other posters address this point.
Yeah.. now that I've actually figured that out, it does seem like a "You're not camping? Why?" situation. I guess I'm just use to going back to the nice comfy beds with showers that don't have lines.
I know you didn't ask for my 2 cents on this, but here it is. Imagine leaving the festival grounds after the late night ____ set, having to get to your car, driving in a long, slow moving line of vehicles just trying to get to the highway, then driving that painfully boring stretch of road for 45 minutes to get to your hotel. At this point you'll inevitably pass out, but only for about 6 or 7 hrs, because you have to wake up and make the pilgrimage back to the festival to see the early bands.
Imagine doing this 3 or 4 times.
No thank you. I'd rather walk the 2km back to the campground and get a good drunk on so I can sleep through the noise.