All true, but the next question is: would a thief not steal a MacBook Air if they are only getting €400[0] rather than €800? IMO, halving the reward won't make a dent on the rate MacBooks are stolen, whole inconveniencing everyone else who cares about aftermarket repairs.

0. Actual thieves are unlikely to sell their wares at anything close to full price, unless it's a an organized ring - so the actual difference might be between getting €200 or getting €100. Either is free money, from thieves perspective