For some added pedantry: aren't all the mistakes that a professional might make, also ones an amateur would make?
In fact, it seems like an amateur is likely to run into all mistakes more often, thereby making all mistakes amateur mistakes; unless there some class of mistake that amateurs are better at avoiding?
In fact, it seems like an amateur is likely to run into all mistakes more often, thereby making all mistakes amateur mistakes; unless there some class of mistake that amateurs are better at avoiding?