Gosh, I wouldn´t have ask for dropped bags. It´s about Pouches, leather Bags
(those who are craftable), Backpacks, craftable sacks and so on.
They don´t disappear when dropped
(I got a test running ... since 6 month - and they´re still there).
I also tried it in GM-Mode and afterthat renamed a sack to "N don´t work".
(You even can´t destroy a warehouse, when a pouch is in)You can´t sacrifice them.
I´m not sure if it´s a bug or not - and some Player uses dropped bags with one Pouch (or maybe Jugs) in it instead of warehouses (cause they fit 10k Stones) - but if it is no bug, you should be able to destroy them.
Our Tailors made serveral hundrets of them ... just for skilling.