Actually, your worst fears about the evil Back Button, though perhaps initally
griped in jest, are well deserved.
There is a security bug in Microsoft Internet Explorer that allows
scripts to be embedded in URLs. When you press "back" from a
"Local" Internet zone such as an error page, the script is executed
in the Local zone. A malicious web site could then read files on your computer,
execute programs, and delete your 20 page E2 writeup drafts.
More details: http://online.securityfocus.com/archive/1/267561.