Our university was far less careful, and just ran our submissions in the same network as everything else albeit on a user with barely any permissions.

Once when the automatic tests crashed my submission, I simply used `system` to dump the testing input into my home dir. I forgot, however, to setup the permissions, so I couldn't really access it! A couple more resubmissions with extra chmods, messing up a different thing every time and I managed to reproduce my bug, fix it, resubmit and purge all (or most) evidence.