I use a couple of different MIME clients, none of which have any problems
with
getting at the data in multipart/alternative. The worst I've seen is where
multipart/alternative is treated as multipart/mixed, and this just isn't
that
bad.
It depends on what you mean by "bad". ("Imagine every atom in your body
exploding at the speed of light...OK, good safety tip, don't cross the
beams.") OK, not that bad if you get one of these messages every couple days,
but imagine you have 150 messages in your inbox, every one of which requires
that you go through this multi-step process just to look at what might be a
two sentence message. I think that's worse than bad, that's horrible. And I
can guarantee it would be sufficient to be a deal-breaker in many cases. I'm
sure you're familiar enough with the commercial market to know that pointing
fingers and saying "it's their fault!" doesn't get you very far with a
customer who just wants things to work.
The MIME spec says that "Receiving user agents should pick and display the
last format they are capable of displaying." I'd argue that by just showing
the multipart/alternative object, those user agents have not done any picking.
From a practical point of view, this behavior, if typical of MIME user agents,
makes multipart/alternative significantly less useful. These aren't
abstractions. We give the customer a choice of what format to use, and they
are choosing to use the multipart/mixed form since they find that it
introduces less problems (e.g. users complaining to the mail administrator) in
real day-to-day heterogeneous message exchange. That's a fact, and no amount
of explaining the advantages of semantic accuracy will make them happy. They
just want to read the damn message (and probably delete it).
Terry