[imp] Access to other users mailboxes

[Myke Place]

> You might try upping the amount of entropy to 24 or 32.

I've increased it from 16 to 32. We'll see how this affects things.

> You might also make sure that the people who can reproduce it haven't created
> bookmarks that point to pages inside of IMP.  It's possible that the URL could
> have the sessionID in it.

I've confirmed that this isn't being pulled from a bookmark.

It sounds like this is affecting more people than just us, I'm open to any 
and all suggestions and of course happy to provide additional info. Thanks 
to those who have already replied.

-mp