Some of the best UX is the simplest. I downloaded Google Notifier, mounted the disk image, copied the binary to /Applications, launched it from Spotlight. Naturally, Spotlight chose the version on the disk image, not the local version. Well, look at the awesome dialog that resulted:
Not just reminding me to not run it from the disk image, I’m offered the option to fix the problem right there. I assume this is dead simple to program (unless launched from /app, show…), and I’d love to see it more often. It’s a perfect example of going the extra mile to exploit the sorts of things a computer does best. Even though it’s a small feature, this definitely gets an EPIC WIN.