Bretman, I have seen this called a couple of times over the years (and not called a few other times). You state this is a myth. If so, how does the rule read that people are confusing it? (cant find the rule on the internet and dont have a NFHS rulebook). I would really like to know and any help would be appreciated. Thanks in advance!
Here is the high school rule. This is pretty much the same for any level of baseball or softball.
8-6-5: The runner is out when...Any offensive team member, other than another runner, physically assists the runner.
As a side note, notice that "other runners" are exempt from this rule. It is always legal for one active runner to assist another (runners can't
pass each other in the basepaths, but they can assist one another if one falls or push the other toward a base).
An "offensive team member" would include all of the players on the bench and the team's coaches.
The rule doesn't say that a runner is out if "touched" by a coach, but "physically assisted". This means that the coach must actually aid the runner in some way, or affect her base running. Examples of "physically assisting" might include a coach helping a runner up who has fallen or tripped, a coach grabbing a runner to prevent her from advancing, a coach pushing a runner toward a base or a coach touching a runner to help in tagging up on a caught fly ball, so she won't leave early.
Slapping an otherwise legally advancing runner a high-five does nothing to aid her in running the bases and has no influence on the outcome of the play.
I think that I posted this here earlier, but I can remember there being confusion about this rule when I played PONY league baseball 40 years ago! And I'm sure it caused confusion even before that.
Somewhere along the line, the distinction between "touching" and physically assisting" a runner became blurred...and a rule myth was born!