For myself, I find the Prime position so alarming that I'm tempted to
lobby everyone to explicitly modify their MTA's to reject 8-bit data
even if they can already handle it, just to promote interoperability and
compliance.
I plan to provide three options in the software I write:
(1) Accept nonstandard 8-bit messages without complaint.
(2) Accept such messages but send a message back to the sender saying that
their mailer is nonstandard and should be updated.
(3) Reject the messages.
I plan to ship with (2) enabled. Most sites will probably move to (1), but I
know of quite a few sites that have pretty noncavalier attitudes about
standards who will want (3). In fact, I'm sure that if I don't provide (3)
as an option I'll get yelled at for not doing so.
Ned