Metaphorical article of clothing, the invocation of which indicates the "wearer" is exhibiting spectacularly bad judgement. Inspired by the 1990 "Saturday Night Live" sketch of the same name.
"You left your bike outside last night without locking it up? Those Bad Idea Jeans look great on you."
"I can't believe I went home with Butch last night. That's what I get for wearing Bad Idea Jeans."