Source:
https://blog.cloudflare.com/perplexity-is-using-stealth-unde...
Perplexity's defense is that they're not doing it for training/KB building crawls but for answering dynamic queries calls and this is apparently better.
However, if this information is accurate... perhaps site owners should allow AI/bot user agents but respond with different content (or maybe a 404?) instead, to try to prevent it from making multiple requests with different UAs.
These had the same user agent (latest Safari), but previously the agent has been varied.
Blocking this shit is much more complicated than any blocking necessary before 2024.
The data is available for free download in bulk (it's a university) and this is advertised in several places, including the 429 response, the HTML source and the API documentation, but the AI people ignore this.
If web security worked a little differently, the requests would likely come from the user's browser.