I voted for 2 - fast and furious and don't bother to cover.
Halo does her business. While still standing in the cat box, she digs furiously at the carpet (not the litter) then jumps out of the box. She knows to go in the box. She knows she's supposed to dig something. But, she's never figured out she's supposed to dig the litter. Then she jumps out leaving it uncovered.

Cammie doesn't bother to cover. Pepper sometimes but most of the time she's in too much of a hurry to get back to playing.