I suggest rewording the above to "Since filling the CSV file can be…"

I suggest rewording the above to "As there can be many fields in the CSV file, another option has been provided to make life a little easier:"

I would probably just s/notification.*/notifications./ and change "The" to "This" at the beginning of the sentence.

IMO, incorrect data is worse than missing data. I think we should set the e-mail addresses to NULL if we don't know what they are.

pagure won't allow a username without an email id.

I think a better approach would be to set the e-mail address to NULL in the database, so I am a -1 on this proposal.

I am not sure what to do here. I tend to agree with @bowlofeggs.

I was just thinking that before populating the csv with fake data we could check if the user as the same username in github and fas, if so we can get the email address from fas.
This should reduce the number of empty emails in the csv.