That is an interesting issue you bring up. I have given kudos to a post before, and then the person posts again, which is added to the post, and is something to which I do not wish to give kudos. It makes me think about withdrawing kudos, but I typically just leave it.
"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.