It is always unfortunate to hear when students undertake these actions. Unfortunately we cannot prevent this. It is also impossible to find out who did this and we are not legally able to do so, partly because of the GDPR.
It is good to indicate how this situation occurs.
In most cases, these are students who pass the code on to students in other classes.
We therefore recommend always closing the pin code and teach to a class in LessonUp where the students must be logged in and the pin code can be closed by default.