Purchasing meaning one MUST register with BlueTooth SIG .. WHY ?

Question

Developing IoT product using a module using Nordic nRF52832 - using their Shockburst protocol 
 
 Can ANYONE explain why we would need to be registered with the Bluetooth SIG and be subject to 'royalties ' if ordering such modules ? 
 
 Not using BlueTooth nor mentioning it in advertising / tech specs ?

Andy · Answer

A long time ago I was looking for information about developing products using CAN bus (an automotive messaging protocol). I found out that if you wanted to develop CAN products you needed to pay Bosch a huge fee upfront and royalties of like 1% per piece. 
 After sometime I realized that this fee is meant to be for other semiconductor manufacturers, so that royalty you pay is kind of already included in the price of the IC. Maybe this is a similar situation where Nordic pays royalties to the Bluetooth SIG and you just have to pay for the price of the IC. 
 This is just speculation though, but I've never heard of anyone paying Bluetooth SIG any royalties.

Andy · Answer

Ok, so I was just told that you don't have to be a SIG member as long as your device doesn't communicate with 3rd-party BLE-enabled devices. Apparently you do need the membership otherwise. 
 In any case, I didn't find anything about royalties, there's only a product listing fee of $8000 USD ( https://www.bluetooth.com/develop-with-bluetooth/join/membership-benefits ).