This would not solve anything. Abusers would just send fewer merits multiple times. Legitimate senders would be inconvenienced. You still wouldn't be getting those merits unless you otherwise deserve them - you realize that, right?

Merits are not scarce. Theymos can produce any number of them at any time. Meritorious posts are hard to find. That's what we should focus on - create and share quality content.

Someone wasting their airdrop merits on their alts is an evolutionary dead end. Let them die in peace.