Except each time you rinse and lather, you are emptying a large shampoo bottle, throwing away most of it, getting a capful back and having to buy a new bottle to repeat. It's not worth the hassle, not to mention the consequence should a Marriott agent look at your account when you are begging for the hotel points to be redeposited again and thinking you are trying to commit fraud. No account means you lose everything.

If it were a worthwhile endeavor, you'd see evidence of it on certain threads and boards.