Bots are better than humans at cracking ‘Are you a robot?’ Captcha tests, study finds
(www.independent.co.uk)
And TBF just getting on arxiv also means you jumped a bullshit hurdle: Roughly speaking you need to be in a position in academia, or someone there needs to vouch for the publication. At the same time getting something published there isn't exactly prestigious so there's no real incentive to game the system, as such the bar is quite low but consistent.