Some of the systems integrated well ASCII fallback. However it was with experimental EAI, those newer systems have not created any mess in my tests. But, even if I want to agree with those who says that if you have EAI why do you need ASCII, it is literally because of that ASCII fallback that seems to be working in some systems a decent job. Otherwise, everyone will abandon EAI and just use ASCII, because EAI doesn't work (every time).
If you say so, but I have never seen mixed EAI and ASCII mail systems that really work. People end up using their ASCII addreses because they know they can write to everyone. At one of the ICANN tech days we heard about a community of EAI mail users in Thailand where everyone was writing in Thai. I also gather there are EAI mail communities in India where people are writing in Indian lanauges. That seems a lot more plausible than somehow figuring out one address at a time who you can write to with EAI addresses and who you can't, and trying to figure out impossible combinations of mail to groups of people some who have EAI addresses and some don't. Regards, John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. https://jl.ly