Further information that I have received from Aquiname on RIMROAD indicates a potential trespassing issue with the BYOA concept -- because you still have to go through a carrier-side Blackberry gateway even before you reach a BWC server or a BES server. This is the usual hierarchy for the push email.If you decided to try to bypass the BWC server by BYOA (Bring Your Own Access) with a third party BES service, you still end up with:As a result, it seems like one would now be trespassing a carrier-side Blackberry gateway when one attempted BYOA (Bring Your Own Access). It also indicates Blackberry functionality is likely not possible on networks that don't have a Blackberry-specific gateway, although technically RIM could make Blackberry work (albiet less reliably) over non-Blackberry gateways due to problems with varying IP addresses and the connectionless protocol that Blackberry uses for push email.

Another question is why Blackberry sometimes work on some cell networks that don't even support Blackberry. This is probably because of special cases where the network has set up a Blackberry gateway, but not deployed Blackberries. It would seem that this would probably be considered 'trespassing' by the carrier themselves, even when connecting to a third-party BES server.

It would be really nice to hear an official word from RIM themselves to clarify.