Seen two banned users so far.
1) Seem to be a rumor, no clear if they used public leaks or not.
2) A user that did the "coin" trick to get Nintendo coins again.
Why they acted like they did? Easy... Money!
So yeah kind of an extreme case for a cutting edge emulator. But they had to do these kind of things since Yuzu was a HLE application compared to LLE emulator (Which it seems like Ryujinx seem to be)