He can, and that is not the only way someone can pay to harm another person.
Uh, and what are the other ways to harm the other party?
While you're at it, think why a feature with flaws that you're enumerating is better than the current centralized payment processors
BTW a (2/3) escrow address with expiration (
expiration date in favor of the seller) can be used in this scenario,
that requires the centralized entity to create their own software that supports scripts with CLTV.
Sorry, just have no clue how it could be implemented.
If it isn't a good idea in the first place, there no point of thinking the possible implementations.