I've been living in Finland for the last 20 years, and this story is pretty accurate. I've dropped a wallet to have the finder hand it in to the nearest supermarket, who then contacted me to pick it up. People typically write their names or phone numbers on bus cards, in case something similar happens. Lose a phone? Go to the police station. It's usually been handed in.
If you lose something, you can expect to get it back, unlike what I've found to be the case in my home country (UK). People just tend to look out for each other here.
My partner is Finnish and so I stay a few weeks every year for years. I am Canadian and the cultures are very similar (northern, low population density, WASP-y, racialized immigrant hating - eg calling the dialect of Finnish refugee immigrants speak "bacterium").
If you lose something, you can expect to get it back, unlike what I've found to be the case in my home country (UK). People just tend to look out for each other here.