No, the cartridge door was a safety interlock and an ease of use feature to completely start the machine from a fresh state on cartridge insertion and removal.
Machine won't power up with the case off due to safety interlock.
No RF emitted when door is open as power is off.
You can still hot plug like on an XL/XE just a little tougher to rock a cart in, some dummy carts had a switch to turn on and off cart power, and protection bypass carts etc. were all used without issue, while most folks using them had just bypassed/jumped the interlock to use them.