What does using an e-ticket and selecting your own seat have in common? At least all the self-service machines I've used in HEL can accept paper tickets in addition to your card that's used as the e-ticket key. Works nice and smoothly, even with LH tickets (on LH stock).

And yes, I have been bumped as well when using e-tickets. Just ask at the gate, that's the place where the bumping decisions are normally made. Being there early helps.