How to keep neutral armies marching into my territory

Hello there! Long time player, first time poster, &c.

So the title says it all. I am Spanish and a Milanese boat just landed on my shores with a small banner unloaded and it's creeping around. Any ideas? Or can the AI just go where it wants with no repercussions? If I bump him then war is declared.

I am a holdover from MTW where no enemy army could enter a province without war happening.

In Vanilla M2TW, sometimes the AI just wonders around the map like crazy, especially when it comes to AI armies being transported on boats. The original intention is probably to invade you however the AI gets confused and then nothing happens. You could always use the move character cheat to move that insignificant AI army away from yours, or you could just declare war and attack them. Unfortunately by attacking them first probably means a rep hit for you which is both frustrating and annoying.

Oh and welcome to the Guild!

Thank you!
What is this move cheat?

move_character "FirstName SecondName" x y

Names are usually the same you see in game.
Coordinates(x and y) you will get when using show_cursorstat command.

For further explanation on the move character cheat. Click HERE and read the first post from sbroadbent. This goes into good detail.