We have the inverse problem in the university. We are all (many thousands) behind a proxy, so some popular sites detect the avalanche of request and add a captcha or other anti abuse tool to everyone.
>> Websites can pass the http headers X-Robots-Tag: noai, X-Robots-Tag: noindex , X-Robots-Tag: noimageai and X-Robots-Tag: noimageindex By default img2dataset will ignore images with such headers.<<
>>To disable this behavior and download all images, you may pass --disallowed_header_directives '[]'<<
1) Keep a list of all scrapping tools, versions, user-agent string, and which headers opt-out of each one and how can user misconfigure them to avoid the opt-out.
2) Add a general rate limit per ip, Bonus points for a te4mporal ban in case they don't understand the polite version.
What then happens is all requests to w3.org then redirect to a page explaining how anyone automatically downloading those schemas from those URLs became part of an accidental DDOS attack.