OK, yes, I was working with a company specialising in these types of products for a while. I linked a post above to my earlier post on the topic of shielding.
Britian is quite 'anti free will' in it's governmental policy in many ways and it is not seen as a threat to the empire builders because, well, they mostly control and dominate Britain.. America however is different in that it has more of a tradition of fighting tyranny and so presents more of a threat to the tyrannical and thus is more of a target.