When you do your listing on spirit.com, the jumpseat listing gets you one checked and one carry-on bag.

If you for whatever reason, check in at the ticket counter with out a checked bag, the agents can't wrap their head around why you don't have a checked bag...

"I don't need a checked bag"

"You paid for a checked bag, I need to check your checked bag."

"I don't have a checked bag."

"Your reservation said you paid for a checked bag."

"Im just trying to jumpseat."

"What's that?"