greeting card sites not a problem for LMAP

My experience is that about 2/3 of the greeting card email I get is 
UCE.  For the sites sending other third, I expect their email will get 
through more in an LMAP world than it does now.  They should be happy if 
LMAP takes off!
These sites will want to continue to have their email received.  They 
will typically switch to sending mail that is from (in the header and 
envelope) themselves, and publish an appropriate LMAP record for their 
domain.
The subject and body can say who allegedly caused it to be sent.  They 
will or will not have a reputation for being a source of UBE.  They can 
take advantage of reputation services as they wish; some will be free.  
If they use measures such as rate limiting, or verifying alleged 
senders, it's likely they will be able to maintain a good reputation, 
and their mail will reach its intended recipients. Another option would 
be for them to send the email to the sender, and have them forward it to 
the intended recipient.
Besides, as PHB stated, they probably have to stop doing what they have 
been doing anyway to comply with CAN-SPAM.