If you are teaching introductory or maybe even intermediate students, I would think XDATA would be good tool. It can be fairly difficult to remove or edit for a newbie.
At the end or start of each session, check that each entity has the repective author's name or ID. Radmonly during the session and at the end of the session, add the author's name to new entitites
(defun add_xdata_str (e a v);;;EName APPID String_value
(and (not (tblsearch "APPID" a))
(and (= (type e) 'ENAME)
(= (type v) 'STR)
(= (type a) 'STR)
(append (entget e)
(list (cons 1000 v))))))))))
(add_xdata_str "Author" ename (getvar "LOGINNAME"))
or maybe (getvar "_PKSER") if the software was installed from individual disks.