I doubt any human would solve them for 3 minutes straight, but a bot might. So closing and reloading the page (something a human would do) might work. Of course bots that don't do this will quickly figure out that they should - just like every other attempt to figure out if this is a bot or not...

There is no good automated answer. Things bots do to abuse web pages should be made illegal and then jail (fine...) the people who set the abusive bots loose - but I suspect most abusive bots are foreign and so we can't do anything without sending in an army (obviously unacceptable)