Could friend codes work?

[Russous]

Hello,

I was just wondering. Could something in the lines of friend codes work in a Sonic game? For example, you have a character you want to trade. Your friend has a another character you want. You could make a trade. If the friend code was added, it would give you access to the character and you could trade there.

Was anything like this really tried? I just thought of this. Move this topic if needed. I don't know if it is appropriate for this section.

I am new, so I don't know if something is not allowed somewhere.

Thanks and please let me know if something is wrong.