As it turns out, there was no hostile takeover: The Finnish military was merely conducting a drill on the island of Kamsholmen, albeit one in the dead of night. They failed to give residents any warning, leading to one of them actually panicking and boarding a boat to get off the territory and call for help.
As a neutral country, Finland is rarely in anyone's crosshairs, although Russian forces did rehearse an invasion back in 2014 in the event they ever did decide they want to lock up the Åland Islands, which are part of a key shipping route.
Locals who were gripped with terror got a small consolation prize from Gevalia. The coffee company offered free samples to residents as part of their ad campaign covering “unexpected guests.”