[darklion]

> Why not just let people do what they do with other files and leave it on their desktop.

Once upon a time, upon seeing a disk image open with an app icon, a certain quantity of people would choose to run the app straight off the disk image, likely not understanding the prompt to copy the app to the Applications folder.

Then, sometime later, the disk image would be unmounted (e.g., system reboot) and suddenly the app they had “installed” disappeared.

Rather than force everyone into mandatorily copying apps to the Applications folder, they added a dialog to suggest to the user where the app should go. I will say, though, I didn’t realize it applied to _everything_ outside of the Applications folder. I thought it was only for apps run off of disk images.