Has anyone done a community airdrop with a lockup? If not, why is that?

Seems like it would solve a lot of problems. Even professional long term investors can’t keep their finger off the trigger w/o a lockup mechanism. Can’t expect airdrop recipients. 

Can combine immediately liquidity with a linear vest (eg every block to avoid cliffs impacting market price)

Locking up tokens for a community airdrop could indeed provide a solution to prevent immediate selling pressure. A linear vesting schedule could help maintain price stability post-airdrop. Great idea!