Had a senior student who thought leaving his assignment on the random laptop I had hooked to the presentation-room projector meant it was submitted (these laptops are regularly lent out to students with full admin rights enabled, and naturally I re-image them regularly, especially a few days before they are to be used to present assessment tasks!) And yes, the actual submission procedure (bring the file to me to be copied to the class USB drive - and backed up to the Uni server, though that is my initiative - is in the assignment requirements document they all get.