Good on you. I would have loved to do the same thing. I was in a similar situation.
A couple of months ago I was at a pediatrician's office waiting for my kid's turn. As you can imagine, kids everywhere running around and screaming while their parents seem to be oblivious to all their ruckus. In fact, it was the parents (and grandparents) who had their phones out watching videos AT FULL VOLUME and NO EARPHONES. In other societies, this would not only be frowned upon, but be dealt with via embarassing public condemnation. I would have loved to reprimand the idiots and their idiot juniors, but they outnumbered me 20 to 1.
I have three kids, all are very well behaved and sit quietly wherever we are. They read a book or draw on their sketchbooks whenever we are in a place waiting for a long time. I do not allow playing tag or any horseplay in waiting rooms. I tell them, respect elders, do not be a nuisance to strangers. It's not hard to teach them. During one of our long haul trips abroad, one foreigner told me as we were landing, "Frankly when I saw you settle in your seats with your kids I was concerned that they would be noisy throughout the flight. But they are the best behaved kids I've ever flown with."
Were they born that way? No, it was years of instilling discipline in them. TURUAN SA BAHAY. Teach them to be more considerate of the volume of their voices, the sounds that they make, their sense of personal space and their demeanor. You will be creating better, more socially responsible citizens, absent of senses of entitlement.
Problem with most parents nowadays is that they have been de-sensitized to the screams of their kids, or they simply dismiss it as "bata e." Bata nga, kaya kailangan ng disiplina at paynubay ng magulang.