I work at Verizon Wireless in customer service (which IS tier 1 data) and I actually am in the process of being promoted to tier 3 data.
I can tell you this much - the system we use (ACSS) will prevent non-VZW ESN numbers from being activated by customer service reps, (not sure if by data reps)
I would also like to note that we're not quite as evil as you might think
verizon wireless may have some evil business practices, but they DO train reps to do what's good for the customer. A rep can actually get in trouble for NOT trying to help someone (for example, if you're wasting money on a plan that's too expensive, or going over on minutes or text or maybe just plain not realizing you're a VIP customer and you haven't used your 500 amnesty minutes on a bill two months ago with overage)
Now, wether or not reps actually DO things they're supposed to... well that's another story.