If the answer is "Yes", it is most likely a lie.
Quite a while ago, Mikhail Simkin and Vwani Roychowdhury from UCLA published a preprint about this, "Read before you cite!". The authors present a statistical approach to estimate how many people who cited a paper, had actually read it. Here "to read" means "to take at least a brief look" or even "to download a copy of the paper".
The main idea of the method is to analyze... the number of misprints in the list of references. For instance, if some paper is cited by a bunch of different articles, with the same misprint in the page numbers, most likely the authors just copy-pasted a reference from each other's work, without even downloading the article. As for me, I faced with this a few times.
The final estimate obtained by Simkin and Roychowdhury is that about 80% of the citers don't read (say, never downloaded) the paper they cite.
Thanks to Daniel Lemire for sharing the link on Twitter!