This reminds me of a bug I ran into in some beta software on Windows many years ago:

1. Create the directory "C:\APPNAME-tmp"

2. Change the current directory to "C:\APPNAME-tmp"

3. Recursively delete everything under the current directory.

This worked fine for thousands of users until I came along -- running Windows 2000, with the "C:\" directory read-only for unprivileged users, running as an unprivileged user. At that point it became:

1. Try, and fail, to create the directory "C:\APPNAME-tmp"

2. Try, and fail, to change the current directory to "C:\APPNAME-tmp"

3. Recursively delete everything under the current directory, which is my home directory.

The authors were very apologetic when I pointed out the bug.