Yet they respect a lot of things meant for machine to machine interaction. Like server return codes, cookie negotiations, and CAPTCHAs if they behave a certain

Yet they respect a lot of things meant for machine to machine interaction. Like server return codes, cookie negotiations, and CAPTCHAs if they behave a certain way. So they sometimes hit bollards and turnstiles made for other types of code which executes HTTP requests. So they're bots basically, but better (or suitably) behaving ones.