Varying the "Display-name"

Is the following permitted/recommended?

One message:
     From: John Smith as chairman <johns(_at_)foo(_dot_)bar>

Another message:
     From: John Smith as ordinary member <johns(_at_)foo(_dot_)bar>

I cannot find anything in RFC2822 which forbids it. It might cause
problems in those mailers which automatically produce address
books based on content of incoming messages.

--
Jacob Palme <jpalme(_at_)dsv(_dot_)su(_dot_)se> (Stockholm University and KTH)
for more info see URL: http://www.dsv.su.se/jpalme/