iPhone Battery Replace Led to Thrown Away SIM Card

I recently sent my iPhone into Apple to have the battery replaced. While the instructions said to remove the SIM card before shipping I couldn't open the SIM drawer despite many attempts. I figured, what difference did it make, they don't need to remove the SIM to change the battery. If I had bothered to drive 100 miles to the nearest Apple store, they would have changed the battery and left the SIM alone. Silly me, not only did they take the SIM out, they apparently threw it away since I never got it back. Can anyone on this forum tell me why it was necessary to take the SIM out, or is this just corporate policy gone to an extreme? It took two hours on the phone with Verizon to get them to ship me a new SIM.