I am all for PFDs when riding jet skis, water skiing, wake boarding, operating a small fast boat but where I live PFDs are not mandatory, not even for small children.
Before the RV & while our kids were growing up we were very avid boaters. Our daughter was 6 days old when she spent her first night on a boat, a 21' cuddy cabin on anchor. We had one heckuva thunderstorm that night.
Our kids never did wear PFDs onboard. We had safety rules for them & they were enforced. No walking along side decks while underway. No sitting with feet over the side unless a handrail stanchion was between the legs. As soon as they could swim we had MOB drills in open water so that they would know what it was really like to be out in the open watching their boat get smaller.
They learned that water is a dangerous thing from an early age & to respect it. We never did have one of them accidently go overboard. They know that the coastguard is not going to rescue them just in time as seen on TV.
People do dumb stuff on the water. Kids bow riding is one of the worst. That PFD won't be much use if they go overboard & the boat runs over them striking them with the running gear.