[Coco] OT: Self-modifying email??!!

[Arthur Flexser]

I'm hoping somebody on the list can figure out what is going on here.

A few days ago I received a coupon from Chevy's restaurants, a welcome
for joining their email discount club.  The coupon was in the body of
the email itself, and did not require clicking on a link;   you just
had to print out the email.

I opened it a few times in the next few days, but did not get around
to attempting to print it until about 10 days after first receiving
it.  When I opened the message on that occasion, it appeared different
in an important respect:  The coupon was overlaid with an exclamation
point surrounded by a triangular border, beneath which was the
following text:  "Sorry.  This offer has been viewed too many times".

Aside from the question of why the restaurant would choose to cause
such an overlay message (the coupon still had weeks left until it was
due to expire), I'm puzzled by HOW they were able to accomplish the
trick while the message was sitting passively in my Inbox folder.

To make things more puzzling, the overlay disappeared a couple of days
later, after I complained to Chevy's and they replaced the coupon with
an additional similar email.  It disappeared not only on my copy of
the original mailing, but also on another copy of that original that I
had forwarded to someone.  That person saw the same thing I did:  the
overlay was visible when he first looked at my forwarded message, but
was no longer visible when he looked for it later after I asked if he
could still see it.

If anyone would like to have a look at this unusual message and
perhaps poke into its html code to see how this trick was
accomplished, please let me know and I'll forward you a copy.

I wouldn't have thought it possible for the sender of a message to
affect its content after it had been received by the recipient.  It
seems rather invasive, somewhat like the sender of a postal letter
stealing it back from my mailbox temporarily in order to modify its
content.

Art