Chris,
Spent a while tonight playing around and trying to break things. Added 50 nested directories, and while they messed up the front page a little bit (made it scroll a bit off horizontally), didn't break anything.
Manipulated URLs to change directory into different peoples names, non-existant names, etc.., but to no avil. Got a lot of "illegal directory" messages. Tried moving and deleting adam's and bob's files, but wouldn't allow me.
I did notice, that if you create a directory inside a directory (test1/test2, for instance), if you then go into test1 and try to "mv" test2 (in an attempt to change its name, for instance), it always gets bumped back up to your home directory. The only way to change a name of a file or directory within a directory is to "mv" it to "path/to/file/or/directory/new_name"