Security Issue

[Matthew Tebbens <matthew@micrus-pop.fishkill.ibm.com>]

I'm not sure if this is normal, but it seems that any file owned by
someone else and in one of my directories can be deleted by me even
if I don't have the proper permissions to do so. I also can rename the
file, but I can't alter the file. This holds true even if the file
is owned by root.

Is this normal ?

If so, what things can I do to someone elses file thats in one of my
directories , just delete or rename the file ?

As root, what if I want to keep a file in someones directory without them
deleteing it ?  As I see it now, that can't be done ?!?!?

Matthew