That is good from Finnair to do that. However I think they are not able to do that during peak hours when slot times become crowded.

A bit OT: I forgot to give some credit also on the HEL-ARN part of my trip:
While waiting for boarding at HEL, I was wandering around the desk and began smalltalking with the gate dragon. "Will the plane be fully booked?", she replied "Almost there yes, why?". I said "nothing...just curious". She asked "which seat do you have?" and I gave her my BP. She said "I can put you on the exit row and block the seat if you like". I said "OK I don't bother, thanks! That is nice of you".
I never asked for reallocation of my seat and I am only AY Silver

2nd OT: I have seen many times they block exit row seats for Plat members with blocked seat too and that is well done by Finnair. Were they to enforce priority boarding at Schengen gates, and give minicabin J-opups on long haul to AY-status pax (instead of statusless or other OW pax which seems to be the rule nowadays), then I would definitely move all my SK flights over to AY.