It’s not ‘restricted’ as such.
NAIM simply advise users not to mess with the structure and the content of that folder.
That is why I wrote - provided one knows what one is doing.
I did successfully add folders under my UnitiServ into RIPS/MQ and they were read fine by the UnitiServe. This was on an advice from a trusted source.
So I’m counting that the Core will behave the same.