A site that uses Login With AJAX gets many spam user registrations. They haven't yet succeeded in writing spam comments, but for example three user accounts are all Tatsy1234 with different numbers all having the same email domain (ceoll.com). The site on that domain seems to be made only for boosting other sites' search engine ranking - search engine spam.
I bet nearly none of these spam users would have been able to succeed if Login With AJAX would have a honeypot function in its registration form. A honeypot is a field that is not visible for humans so we can't fill it even by accident, but most spam bots write something to all fields they encounter. When Login With AJAX then receives a new user submission where this field is not empty, the submission is not ignored.
Slick Contact Forms has this feature on its AJAX contact form. It has worked like a charm so far and the code may prove an excellent example.
As an aside, the links to the translators' websites on Login With AJAX's WPorg plugin front page are not working properly.