I didn't miss it, you added that statement
after I read your, unedited, posting.
No, I have not tried to load from an unauthorized computer. iTunes has
never allowed you to sync content from two different machines to one iDevice. This goes back to the original iPod (and I have a 5G firewire sitting in a desk drawer at home that still works just fine). It was to keep you from copying content over to your friends. Not that there aren't plenty of ways around that restriction too.
There are plenty of applications that will let you copy content into and out of your iDevice, look around, I'm sure you will
find them.