I had a short conversation with Michael B about this in March and also talked to one of Whistlers' product technicians that I met at SML (hello Rick U.... if you're reading.)
We had to start somewhere so the list of compatible detectors is limited for now. Once we have rolled out the current product range across dealers we will be looking to expand the choice for consumers and add in other quality detectors to the "compatible" list next year. The only main technical requirement is that a detector has to have a headphone socket.
Our whole approach is perhaps more collaberative that many will be used to but I firmly believe that consumers should be able to pick the best products for their own situation, circumstances, etc and it should all work seemlessly together. That's what we try to achieve.