I very much like the new MapRun6 option not to require a PIN to load the event to MapRunG. However, I couldn't find any information about whether the PIN is required for any stage of the process when using MapRunG (e.g is it required to upload results?). I could experiment on a test course but I might miss something.
As you have seen, by default in MapRun6 the PIN is not required to send the event to MapRunG.
In theory, you could then run with MapRunG and upload a result (without ever needing the PIN)...but the intent is that access to the physical map would be controlled, as having the event on your Watch doesn't help with knowing where the controls are.
A runner using MapRunG needs either, the map displayed on a phone, which requires the PIN, or a physical map. I expect this will suit in most cases, and provides the convenience of being able to setup your watch without needing to know the PIN, but the option is there to still require a PIN to send the event to MapRunG on the watch, if desired.
I hope that addresses your question. If not, let me know.