Re: Trickle it in
This would raise revenue considerably because you could make licenses available world-wide, safe in the knowledge that overseas viewers would actually be paying for the BBC and not just freeloading it.
No you couldn't, because the programmes shown on the BBC are licensed and sold on a per-territory basis. The BBC couldn't sell general access outside the UK - just as you can't legitimately buy a UK Sky card outside the country or get the UK's iPlayer service (there's something else for international subscribers that shows old programmes).
Of course there are well-known hoops some people jump through in order to get decoder cards, usually to watch Sky Sports, but "officially" it doesn't happen.