This is a response to an MUA project that I noticed today: https://moodleassociation.org/course/view.php?id=33#section-2
Which states "Omit email address from attendance page to facilitate smartphone use to take attendance"
I do not currently have an MUA account so I am posting this here instead.
The attendance marking page uses the "Show user identity" setting found under Admin > Users > Permissions > User policies. "Email address" is the default setting - you could untick this box to remove it but it would also remove it from a number of other reports in Moodle that will currently display the e-mail address.
It may make sense for the attendance plugin to have it's own "showuseridentity" setting instead of relying on the core setting - pull requests and funding (including MUA) are always welcome, but if the intent is to make it easier for teacher marking you may be interested to hear that I am actively working on adding support for the Moodle Mobile app - the code in the github master branch already supports student self-marking within the app and I am currently working on support for teachers to mark attendance as well.