What happens if I finish the drive letters? It's just curiosity, but I have a lot of letters and it happens that I float around 20 when I have everything connected
This image is not mspaint. I subst'ed all drives, even B:
Then, I plugged a card reader that has 4 drives. Nothing showed up! So, the answer to your question is NOTHING! You are just unable to add more. Of cource you can use volume mounting as suggested above