I have found dead, decaying Mylar balloons in nearly every park I’ve ever been to. I found one a mile off the road in panamint valley, and one in sequoia national park.
I am a regular wanderer of the Mazatzal Wilderness, one of the most desolate areas left in thw lower 48. In 5 years and 100+ milea of rugged terrain I have found dozens of mylar balloons. Their absence will be welcomed.
They suck.