Let's get real, especially these 3 scrapers help the forum a lot, filling the gaps with features we don't have.. for example because the forum software is old.
I don't disagree with you about these three users. There is another one or better to say two more we can add. Ddmr and tranthidung as far as I know. But in these process we are trusting these people. People changes, they will change too. Any bad intend could create trouble for others. In the mean time you have no choice too.
I think a more reliable solution would be to have purpose-built scraping endpoints that take an API key.[...]
Off-topic: I can imagine a set of new endpoints being used to power a Bitcointalk mobile app. Also, I can imagine the same being used as a way to bootstrap the new forum software (as opposed to a point-in-time data migration) which might allow for the old forum and the new one to happily co-exist for a time.
We can dream for it if we expect Theymos to do something about it. But since you good hand. You can try like the OP patch and hand over the codes to Theymos.