I agree, at the point you engage with some one whom is bothering you by their actions, you are escalating the situation further and also making it personal. Just quietly go get an employee who can help, or find a phone to call for help.
The thing to remember ( and why I cringe when I see parents let their kids run around ) is the law of averages, due to the amount of people onboard, is there ARE bad people on your ship, there are pedophiles, there are rapists ( either have done their time or not caught yet), there are people who steal and scam as a way of life, they are there.
I might worry too much but when our daughters and also our granddaughter were taken on cruises with us, my husband followed them from a distance when they were going anywhere alone. And they were reminded of "stranger danger" and to stay together, when going about their day together, if we weren't there with them.
I don't have the figures any longer but maybe someone in law enforcement might know with an average of 3 to 6 thousand people, how many you would absolutely not want to have access to you and yours.