I prefer (1) as such changes may entail more than simply adding
.example at the end of the domain names.
A little off-topic, but I feel like ranting.
IMO, adding .example to all the domains would be entirely insufficient.
Both people and software are good at recognizing the common TLDs, and
turning something like jrandom(_at_)sun(_dot_)com into jrandom(_at_)sun(_dot_)com(_dot_)example
doesn't change everyone's perception. Too many people will pick up the
"TLD" .com while skimming or reading, too many scrapers will ignore
If an example is to be changed and still keep its value to the reader,
then it has to be edited with care. A global search and replace isn't
And an on-topic remark: I tried to edit the examples in either 2821 or
2822 into 2606ese a couple of years ago, but gave up. 2606 didn't
provide enough domains for me to do the job well. Maybe a better editor
could do it. Or maybe not. Jon Postel chose to use more domains than
2606 provides, and IMNSHO Jon Postel was good enough at writing RFCs.