High severity, This issue is separated from the flawed `isDivorced()` check presented in issue #168 as even if that is fixed, if ownership is not checked, isDivorced would still default to false and allow bypass to claim airdrops by posing as tokenId 0 in turn resulting in this [important check for token claim is bypassed.](https://github.com/Cyfrin/2024-02-soulmate/blob/b3f9227942ffd5c443ce6bccaa980fea0304c38f/src/Airdrop.sol#L61-L66). #220 is the most comprehensive issue as it correctly recognizes both issues existing within the same function.