We didn't like the ethics of it, especially since we couldn't guarantee that the bogus data was going only to the attacker (rather than to innocent but not-yet-authenticated "general public").
I guess you could have required login to show prices to suspicious requests. Then it shouldn't affect most people and if it accidentally does the worst outcome is they need to log in.
Oh, lord yes! Frequently they're scraping us from multiple distinct CIDR blocks simultaneously. But we can tell it's the same organization doing it not just because the requests look similar, but it's even possible occasionally to see a request for a search from one CIDR that's followed up immediately by requests for details for the products that had been returned by the search.
While at the same time, because our site is B2B ecommerce, where our typical customer is a decent-sized corporation, it's not uncommon for a single legit user to have consecutive requests originate from different IPs, as their internal proxies use different egress points.
