That works when you're root. It doesn't work when you're just an average user.

Even as root on multi-user systems, I'd rather not give the users training wheels, as it teaches them to be sloppy, and to learn to do things wrong. (Like when I had to explain to someone that 'rm *' doesn't prompt you for which files to delete on every unix system... but the sysadmin on the system they learned had aliased 'rm' to 'rm -i')