I am sorry, but I need to ask this and this seems like best place to do that. What would happen if for example:

I have PAL 3DS
I have PAL and NTSC game.
I put PAL game inside and click start button to start game.
Right at the Nintendo 3DS boot game screen, I swap game with NTSC one

What would happen with 3DS? Because I know that similar was done with GameCube discs for Wii before Nintendo blocked it with update so you couldnt swap discs.

Also I remember that one Pokemon game for DSi was region free. About 3DS region locking, can a developer choose to make game Region Free (like 360 developers for example), or all games will always be locked due to 3DS software???

 

What if someone does modification on game card and remove pin #7?

 

thanks for answering, but you said that developers cant decide if its region free or not so that would mean software in 3DS indicates should it play or not. But how come DS games and Pokemon DSi work on 3DS without regional restrictions

 

Cart-swapping was killed with the DSi.

Still worked on the DS/Lite, but those are region-free so...