That's actually a very good suggestion hatter, but there's a small problem with it. It would punish kingdoms that get those test accounts, as they'd have a useless province for maybe a week or more which is then removed again. Most kingdoms are smart enough not to ask for info right away, might take as much as a month or more. If you're going to take up a slot in a kingdom for a week, maybe reward kingdoms who don't fall into the trap with a little bit of science, honour or whatever.

I'm still in favour of the welcome system, where all players are given a small chat with an official rep about the game, explaining that it's important to get in touch with their kingdom and that they should not hand over their account info.