Can I sub for a teammate in the same game?

[lch]

Yeah, the game actually stores both a registration number and a "compnbr" in the *.2h files. I wanted to quote somebody who told me that playing turns for different nations with the same machine was okay, but it turned out to be atul himself...

<atul> You can. The check prevention just happens if you play with two different machines with same Dom key code in it.

Which would explain why local games and hotseat games work the way they are done.