If it was intentional a more informative error should have been used. I'm sure the ops team at mtgox is quite experienced but these basic errors pages seem like a big oversight once you are running a fairly high trafficked site.
This seems to be an attempt to keep costs low. Most cash drawers have a simple cable connection to the printer which can send a signal down the line to open, very simple. Adding a wireless adapter to the cash drawer would certainly be more expensive.