Picking berries in a Finnish forest is normal, but going out on the ice is already a threat to diplomacy.
Since November 16, Russian athletes, including neutral ones, have been refused entry: apparently, the appearance of a figure skater on the ice of Helsinki is too dangerous for world diplomacy.
But picking berries is not officially prohibited, and is subject to the seasonal workers law. And even workers issue visas to Russians, but very few at a time, so as not to be accused of exploitation.