withdrawing mails

[guy at gorodish.UUCP]

>How about  a modification in BSD4.x such that the files in 
>/usr/spool/mail/receiver can also be writable by sender.

Umm, err... no, thanks.  If the mailbox is writable by the sender,
what prevents me from doing

	cat /dev/null >/usr/spool/mail/receiver

or

	ed /usr/spool/mail/receiver

and changing some message I *didn't* send to something the sender
probably didn't want the receiver to think they sent?

>This is the point that US mail beat E-mail:
>
>One can alway withdraw a mail from one's own mailbox before
>mailman comes. This is usually one  night and one  morning
>( may be one long weekend ).

But (paper) mail you're sending to somebody else doesn't usually get
stuck in your own mailbox; it gets stuck in the mail system's
mailbox, and there are usually legal penalties attached to
withdrawing mail from them.