So, forgive me if I am being obtuse, but......does, or can, Verizon actually tell if you're on tetherberry?
B/C I am already paying through the nose for services.........
.....and what do you mean by RIM's servers? Doesn't all traffic go through Verizon anyway?
Yes, they can tell if you're on tetherberry.
Whenever you use data on your blackberry, all data goes from your phone, through Verizon, to RIM servers, and then to the internet. Your speed depends on the weakest link. The RIM servers do not provide you with the same pipe a direct connection to Verizon does.
Translation ... when you use tetherberry, you are still going through the RIM servers when you tether to your computer, giving you a slower wireless broadband experience, and violating your TOS.
If you pay for tethering, your blackberry disconnects from the RIM servers, and goes directly through Verizon's pipeline, which will be faster.
Now, if you're just using it to check e-mail when you don't have access to a wired or wireless connection, you'll probably be fine and not notice the difference. But if you're looking for a true tethering experience, you'll want to do the tethering through vzw, because it will be faster, and you won't run the risk of being charged ridiculous fees for inappropriate data use.