But... that sounds like it DID work.
Let that child take over doing their own laundry. Problem solved. That problem, anyway.
My oldest used to do this. On the last day of our summer vacation about 5 years ago, dh spent the entire day doing laundry while the rest of us went to the beach. When we got home 2 days later, the kids were told to put their things away. A few days later, I went to collect the laundry from each kids' room (they each have their own hamper). Dd had dumped her entire suitcase full of clean, folded clothes into her hamper, along with dirty stinky towels and wet suits, so it all had to be washed again. That was the last straw. I refused to do her laundry anymore, and she has done it herself since. She hates it, and does a crappy job, but oh well. They're her clothes, her problem.
When I fold clothes, I stack them by person. I put away my and dh's clothes. I take dd2 and dss' piles into their room, and they put them away themselves. At least the clothes end up in the right room. If they end up in the wrong drawer, that's their problem. :D