These students are giving away someone else’s email addresses. They may deeply care about their own privacy and not care about the privacy of their friends. Plus giving away just email addresses (assuming there was nothing else) for a free pizza is not necessarily any invasion of privacy as these can be simply made up.

So I wouldn’t draw any conclusions from this exercise.

Also says nothing about the validity of those emails.

Sure they can have my friend börg.börginson@notyourbusiness.com email address.

I think they mean morally on the part of the student