To educate or not

Typically I don't intervene when someone ( like a parent) tells someone else ( like their child) wrong information, for instance medical information. I don't feel like it's my place to "be all know it all like" and educate them, they do work with a certification in the medical field. Does anyone else? Do you think it's our jobs as licensed professionals to educate certified persons? I know it's our job, duty, and job description when we are staff and we are their supervisors but in the real world off duty is what I'm referring to.

A specific example would help. There are too many variables to answer the question, otherwise.

I tend to stop correcting people when they say they "caught a cold" or "caught the flu" because they had taken a shower the night before and slept with wet hair.

My pet peeve is hearing someone say that poison ivy is contagious. I've gone round & round that argument with my husband...repeatedly. But at least he is a layperson. I've corrected coworkers when we had a child come thru with poison ivy rash & they were all wearing gloves, smh!