In Germany, airlines have a strong incentive to refuse any refund. Courts are very slow to render decisions and the worst that can happen is being ordered to refund the original amount. Behaviour-correcting damages do not exist under German law. In combination this deters some passengers from pursuing their claim.
Edit: Airlines would also be ordered to pay court and lawyer fees which could be construed incentivising. Yet both fees are statutory capped and quite low for the average ticket price.