Like most things like that though, turning right doesn't preclude you from taking off for second, so it's kind of silly. Had a coach pull that against us once, kid turned right then took off for second, stopped and walked back. We tagged him, was called out and the coach screamed and threw a tantrum that he had turned right. Ump, actually pulled out the rule book, showed him the section (one of several he had marked in his book) and told the coach to buy a rule book and go sit down. Was kind of funny.

No, it isn't a rule, but as Nortaz points out, turning right removes the subjectivity and I'm sure there are a lot of umps, especially in youth ball where the umps are just kids a couple age groups up, who have heard it as a rule and will call it.

I also had my 1B keep an eye on it and if a kid turned left, go over and tag him and toss it to the pitcher, if nothing called don't make a big thing of it, but we did get a couple cheap outs that way over the years.