A small mockup based on my previous idea. We used to have a warning like that in nautilus, but this one isn’t just informing you about a possible problem, but giving you a tool to get what you want.
Creating a special type of view that I mentioned last time does sound like a headache, since we don’t really do that anywhere on the desktop and like Steve mentioned in the comments it may cause confusion to show a different view depending on the contents of a folder. On the other hand obtrusive dialogs are not very nice either. So maybe this whole idea isn’t so good afterall.