[mitthrowaway2]

Whether it should or shouldn't, it did. But I think the issue is less that it happened, and more that the user interface doesn't respond to the "no permission" error by offering up a button you can click to attempt to grant yourself permission. If it can be done through the terminal, there should be a novice friendly way as well.

(For that matter, a novice user shouldn't even have to know how their external hard drive is formatted! It might not even be their drive; it could be a family member attempting to share photos with them. If they're just plugging it in for the first time and seeing errors, they'd be pretty hesitant to mess around with the terminal typing in commands they don't understand).

[amlib]

Sorry, I didn't mean to imply this isn't an important problem that needs to be addressed. I mostly agree with what you say and I bet the right way to deal with this is to have it be mounted with a special user space filesystem like fuse that wraps the permissions to always look correct for the user that mounted it, but I guess no one so far has decided to take upon such task...