[half-kh-hacker]

If you get allocated a /32, you have 95 bits of addresses to play with. You could use a different IP every millisecond and not have problems.

[deadlyllama]

Yeah, but they'd all be in the same /32, which is trivial to block. You'd have to intersperse "legitimate" users through your space to thwart that.

[near]

What would be wrong with blocking the entire /32 if you know the owner of it is using it in such a way?

[citrin_ru]

Ad trackers often use some ISP or cloud provider with many other customers. Which network ISP assigned to a given customer is not public information. Even if a company has own AS, blocking it not always an option: Google, Oracle, IBM and others potentially can use any IP in their networks for Ads, but too big to block.