Post your examples. Today, a few turns after founding my first settlement on Conquistador difficulty, the English AI settled just a few tiles down the coast. They settled their soldier and left the pioneer out to improve tiles. I just had my soldier grab his gun (I settle both initially) and walk right into the undefended city. A few turns later, the AI brought some more colonists and settled another undefended city in the same spot, which I took again. This happened four times before Washington went elsewhere.