Mailing those things was fairly common, but copying the backside was a trick.
Copying might be a trick. I'd broken the Lotus 1-2-3 copy protection and used the same method to encode my map data :-O (There's three critical timing bytes in a particular Apple II OS location you can twidlle in and out.)
I've lost track of the state of "universal diskette copiers" but maybe something exists now that will recognize the encoding difference.
I forget where in the game code I buried the timing / access stuff. Probably some "call -THISTHING" reference in the basica code?
It's been awhile, but I remember the game prompts the user to switch diskette sides and press enter before it accesses data. Probably near that code-path.