I've heard from teachers both before I started teaching and after that students would often falsely accuse teachers of losing their work just to get out of doing the work. Yet we also know that some teachers really DO lose student work. We can't afford to pretend either of these things never happens, and as well, finding out who's telling the truth and who's not is a vital clue to who not to believe on other things. I don't recall hearing about that one in teacher training in particular, though. Are they too worried about offending voters to mention it in a publicly-funded program? Because I would think having a standard set of practices for dealing with this sort of thing (eg. scanning all assignments collected, etc.) might be more efficient in catching the liars. Or is it just a matter of having a "standard practice" meaning that you now have a standard set of ways people will come up with to get around it?