Early dye-sub printers, especially 8x10, had heads that had to be locked in place for transit. Older Kodak printers had pins that needed to be installed and the Sony UP-D70 had a combination of left arrow, right arrow and Stop that had to be pushed while the unit was on to lock the head. All of these printers needed their paper and ribbon removed from the printers for transit too.
Recent dye-sub printers do not have heads that need to be locked for transport, but do need to have the paper and ribbon removed. You do not want the paper and ribbon bouncing around and potentially damaging the printer's electronic and mechanical systems. This type of damage can also void the warranty since all the manufacturers recommend removing the media. Please keep this in mind the next time you take your printer to an event!