Though I agree those would be hard captchas if you tried to complete them properly, It's not overly hard to guess which one is the control- the control is alway

Though I agree those would be hard captchas if you tried to complete them properly, It's not overly hard to guess which one is the control- the control is always bold, very likely a nonsense word, and never cut off or partially visible, because the control is generated by an algorithm rather than a scanner. The captcha isn't really designed to be regenerated until both words make sense.