I had a student use a VERY offensive term in their display name this week. It was very upsetting. Within a few minutes they also entered extremely offensive and pornographic images in an individual handout--and I can't track them at all because I can't see their school email address, only their offensive name! My school is struggling to deal with this.

I agree. This is something that needs to be fixed. Even in face-to-face interactions, if a student puts a fake (or another student's) name, it causes problems. I know this is mostly a classroom management issue, but if there was no option for names or a way for teachers to lock in correct names, that would be helpful.

In some other programs, students' emails are collected and matched with their ser name.
This way I can still give them their marks and deal with inappropriate behavior directly with that student

Many of my K - 2 students can barely read. I can ask them to click on the "blue" button to enter the lesson. But many of them get only that far. Also, many of the parents are concerned about their child's anonymity in the lesson, and do not wish to display their child's name. For this reason, it would be VERY helpful to be able to see the children's login emails, so I can grade them more easily.

I have a student who has signed in and will be working with students in the future, but used a fake name. Remotely, no one wants to work with them. They are unidentified and I cannot tell who it is either.