NC just in case.
Daughter is angry this eve as a mature student on her course has mistakenly replied all to the class, instead of just her lecturer. In the email, apparently they brag about finishing their assigned work early, and then flirt about a shared hobby with lecturer. Daughter wants to bring this up formally with the institution along with other friends of hers. I haven't seen the email so I'm not sure what "flirting" is but I suspect the mature student, being older, just shares a hobby with lecturer (and likes being teachers pet).
My advice to her is just ignore the mistake, keep your head down and make sure your own work is done. AIBU?
I'm not sure why DD is so exasperated by this. I'm sure many emails fly about all day in academia.