As the super-awesome-guy originally mentioned, let me reply to the comments.
"Sounds like the type of guy that would learn how to mod just to give himself a gazillion soldiers and a super-ruler for free too."
So, the guy who is able to completely roll through England is one of those guys who "needs" more help. What? How do I need help, I'm completely owning this game IN MY FIRST WEEK! Yes, clearly I want it to be EVEN EASIER!
I'm one of those guys who builds mass huntresses in Warcraft3 because they're broken. I don't need to cheat to win, but you do need to fix your game if I'm just winning without even trying.
"In the meantime, by pre-placing his armies, he will prevent the AI from raising those levies. Which means longer sieges. Which means he's paying more in upkeep than if he had just let them raise their men and fought them in the field. Personally, I think it's a silly strategy"
Money is easy to get and Mercs aren't that hard to maintain esp if you use them like the fodder they are and get them murdered so I can hand out fewer paychecks. Mercs are also SUPER CHEAP in mid game. It costs like 50 gold to go on a grand hunt. Mercs cost 150. I can pay an entire army with what it takes to hold a feast and go hunting. That isn't expensive, that is the deal of a lifetime!
Also, I don't have to "camp" my mercs. They can move, murder everything, then I can form my own levies at my leisure and win.
"Sneak attacks are sneak attacks. "
Yes, It is a sneak attack that I'm marching over 3000 troops into your capital city while you watch. Then afterwards, send a messenger to inform you they are hostile.
"And the rest as they say, is history."
Funny, I remember history being full of really bad things happening when Mercs are disbanded. In fact, isn't most of the "100 Year War" just Mercarcies refusing to go home because France was beaten and they could just keep looting and doing whatever they wanted. It's a game, which requires balance. Otherwise everytime I crush you with mercs, any unclaimed lands should be taken by the mercs.
"Not really an exploit. Unless you can tell me when in the history of Europe you had to disband your entire army before you could declare war on an enemy."
Yes. Expect you have to disband the parts of your army that have peasants in them.
"Mongols"
What are you talking about, I can't play them.
Anyway it's also really cool that something isn't total cheese against the AI, but is total cheese against humans.