Yup, you could certainly do that... but then that's not exactly automatic is it?
As I said Brian, I am no expert with this topic. The way it was described to me made quite a lot of sense (given that it was explained much better than I have explained it here). The point seemed to be that this is probably the easiest way to transfer malicious code, and so Apple deliberately avoided support for this feature.
Personally, I am yet to come across a disk that does successfully auto-run in OSx, but if it's possible, I'd love to know how. Do you still have the disk??