Gaming Wheres my games gone?

[Cyan]

I have a question myself. What if you downloaded the games from your DSi to SD card A, and then put in SD Card B and redownloaded them. Then with SD card A, you transferred the games to a 3DS. What happens if you put SD card B into the DSi? Do the games still boot up, or is there another measure?

No, it won't boot.
When transferring the Game, it actually transfered the ticket stored in the console to the other console too.
The ticket is what tell the console the game you own and already bought.

The DSi don't have the information that you own the game present on your SD cardA so it can run them.
In fact, the last step "game transfered from DSi to 3DS" in my previous post is not needed, you would just need to download it again from the eshop as the 3DS have the ticket for that game now.
what's important in the consoles is the ticket, not the game.

I added the "ticket is moved to the other console" step in my previous post.