A: Of course it's reasonable to wonder why a 5-year-old still has a pacifier. Perhaps there is an alternative explanation. Is it possible the older child was goofing around by putting one of his sister's pacifiers in his mouth? Or is it possible this child has special needs -- such as a sensory issue -- and uses a pacifier as part of his treatment?
The more we're exposed to other families and their parenting styles, the more we come up against very different approaches. And certain issues tend to be "triggers" -- the use of pacifiers is certainly one of the common triggers that raises strong parental opinions. But despite this, it's best to respect others' approaches, unless the child is in danger. Your school, I'm sure, has policies regarding pacifiers, and I would defer to your administrators to make the call on this one. Being a parent is a steep learning curve for all of us, and unsolicited advice is usually not received well. So unless the other parent asks you for advice about the pacifier -- or any other parenting issue -- it's best to keep your reactions private.