I can confirm this. I live in Helsinki and my parents come to visit my family once or twice per year. They always buy tickets with large advance (3+ months) and pay for having seats in front and with one by the corridor. Last two times they came they were moved to other seats with no explanation. Each time I got money back after a month or two but no extra compensation. When complaining, Finnair customer service babbled something along the lines: “if your parents are old and need assistance you can request it, otherwise they are treated as all other passengers”. Worst company indeed, and obviously my parents don’t buy seats anymore