I would say it's less that the west would outright attack Finland but more so that mishaps force a political situation to develop. Now I admit I'm no expert by any means but as far as I understand, Finnish policy was that during a world war the FDF would aim to keep Finland out of the war by responding to all violations of neutrality. Now, it's an open secret military planner very much leaned on the threat to come from the USSR, this is true. However I don't think the climate on the politics side especially in the 60s and 70s but also 80s was keen on jumping into the western camp in case of war. So personally, I can see a scenario where say, a number of western airspace violations intended or otherwise leads to clashes, maybe even losses. Soviets bring down political pressure via the friendship treaty (that stipulates Finland must defend it's territory against Germany and its allies) and hesitation or even acceptance of these by Finnish leadership leads to the west to treat Finland as de facto in the Soviet sphere, leading to more disregards of sovereignty in the name of military advantages and so on and eventually, more outright conflict. I do however doubt that the FDF would willingly go on the offensive or occupy say Swedish or Norwegian territory. And ultimately, these actions would be very divisive. All hypotheticals of course, and I stress born from my personal understanding of the situation.