[bisby]

no? A file system is the format that the data on the disk is stored as. If you mount an ext4 disk as ntfs, it wouldn't load properly. It's not just the interface for loading the data, it's how the data is actually stored.

[crazysim]

What I mean is that it should ignore permissions on external ext4 by default in Desktops.

[jolmg]

There's no concept of "external". What would it be, "USB" or anything mounted under /mnt or /media? What if it's the root OS drive of another computer you're trying to fix connected through a USB-SATA adapter? Should any program running with minimized privileges get to overwrite even root files in that OS drive?

I think that it's a pretty good heuristic that if permissions exist in the filesystem, they matter and shouldn't be ignored.