On Ubuntu, in what kind of situations, if any, running a command as a non-root to access a file/folder or create/delete a file/folder using sudo may result in "permission denied"
while running the same command as root user would succeed? The user is assumed to be a sudoer, of course.

Practical example on Ubuntu 12: I've got this directory in / with root:root ownership and drwxr-xr-x permissions and I tried sudo date > file while in it as well as sudo date | tee file but got the same

-bash: file: Permission denied

in both cases. Sure enough, there're no problems if I'm root. This is quite frustrating.