"Cost. I've been to Jackson's Whole. Producing one accelerated clone is fucking expensive, beyond most people's means. Producing ten, beyond all but the richest. Producing fifty - at that point they might as well just buy several mercenary armies and wage open war. I might grant that they could have two, if they desperately wanted to, but they could only send one to Barrayar in my place - any theory that assumes they have the means to send both strongly implies they also have the means to swap them in for me without waiting for me to fall into their collective lap on Earth."