> which is basically why after a single reCAPTCHA solve, you wont see them prompt you again for ages - they know who you are.

If only. If the same site has reCaptcha across more than one page, within mere minutes of having to slog through multiple screens of one, I can guarantee I'll be doing it again.

And I'm never sure if Google has served me either a very long sequence of reCaptchas, or whether they've decided I'm not a person and are serving me an infinite reCaptcha.