Yeah if I saw that I would have just thought that it was sponsored to show up first in the list of items or something minor like that, and not that it wasn't part of the original list at all.

I could spin it as well-intentioned. Regardless of whether the list-maker requested the item, you don't want to buy something that's already been purchased by someone else.

I'm not willing to give Amazon that benefit of the doubt, however.

Well intentioned would be to indicate that the product is not requested. Maybe writing 0 of 0 could be acceptable. 0 of 1 is a lie.

If that was the intention, then there could just be a counter indicating how many had been purchased by others, but it only needs to appear if that is non-zero. That seems like the far more obvious way to do it. I don't know how you get to the "0 of 1" strategy without trying to trick people. The 1 is completely made up.