Times change, and I have to agree with Discokid. Many people have said to me that the non-uniformed immigration people in the UK mark something of our civilised approach to doing things, compared with the armed personnel on arriving in other countries, notably the US. But there's no doubt about the faintly intimidating aura of the latter.
That said, even in the US, however, they have become more rigorous on exit checks only at a few airports in recent years, and I don't think they're always tightly policed or the records always updated.