I never clap for something that I haven’t read. However, sometimes Medium might think so because if something is unusually long but I want to read it, I’ll print it out then use it for bedtime reading, then, assuming I finished it, go back and clap and/or comment on it. So I may be cheating some writers out of reader engagement, and if so, sorry. Unless the Mighty Algorithm has a way to detect when an article has been printed and counts that.
Another thing I never do which apparently lots of people on Medium do is follow people whose work I’ve never read and clapped for. I know that a lot of people do (follow people they have never read) because if it were not so my stats would be in the stratosphere. Before I follow anyone I read at least one of their writings and clap for it. If it’s so terrible that I can’t bring myself to clap for it than I won’t hit Follow. If it’s so boring that I can’t finish it then I also won’t hit Follow.