Exactly as I said -- with GSM, use your carrier's SIM chip with any phone you want that's compatible. To get back to the subject, the fact that the carrier lets you use a phone of your choice doesn't mean that the carrier gives you permission to use a base station (cell booster) of your own on their frequencies but not under their control -- regardless of whether you are using their SIM chip in your phone.
What facts were made up? You pointed out that GSM is different from other cellular/PCS operations, which I hadn't taken into account when I made a peripheral comment about activated handsets because I was principally trying to address the question of unlicensed base stations being marketed as boosters, and I acknowledged you were correct about GSM, and that the SIM chip and not the physical handset is what the carrier authorizes.
Michael D. Sullivan Bethesda, MD (USA)