> IANAL but my understanding is that violating the ToS is only ever a problem if your crawler decides to "sign-in"
Where on earth would you get that impression?
From the reddit ToS: "To use certain features of our Services, you may be required to create a Reddit account (an “Account”) and provide us with a username, password, and certain other information about yourself as set forth in the Privacy Policy."
NB: "Certain features", that clearly means that features are not gated by sign in, and that the ToS also applies to them.
Also from the Tos: "
Except and solely to the extent such a restriction is impermissible under applicable law, you may not, without our written agreement:
license, sell, transfer, assign, distribute, host, or otherwise commercially exploit the Services or Content;
modify, prepare derivative works of, disassemble, decompile, or reverse engineer any part of the Services or Content; or
access the Services or Content in order to build a similar or competitive website, product, or service, except as permitted under the Reddit API Terms of Use."
And later: "Access, search, or collect data from the Services by any means (automated or otherwise) except as permitted in these Terms or in a separate agreement with Reddit (we conditionally grant permission to crawl the Services in accordance with the parameters set forth in our robots.txt file, but scraping the Services without Reddit’s prior consent is prohibited)"