Is it still worth it to follow every link on Facebook and check the URLs/AJAX requests whether the parameters can be tampered with? At Facebook's scale I always assumed there would be someone full-time employed to do this. In fact, I wouldn't mind if it was good paying. Just give me all the Facebook frontend endpoints and I will go by them one-by-one. Manually. I will even document the test cases and what could be intercepted, changed or can be improved in terms of validation.