iI've used harnesses for my two and never had a dirty look or negative comment. Actually, the people at airport security complimented me for them--they said they would rather see people use such devices than have to do an airport-wide search for a missing child!
However, here's a little secret, shhhhhhhhhhhh, don't tell anyone, but this is what I did. Any harness designed for a child is much too flimsy for an active kid. They are designed to break away with the slightest pressure, presumably for safety reasons, buy, hey? Who's holding the other end? Its not like he's wandering around with a harness and no adult attached to the other end. I went to Petco and bought dog harnesses and leashes. Just study the "kid-type" you'll find dog harnesses designed exactly the same way. That, plus a leash (you can even get one of those reel things to take up the slack), and no one will know you're actually using a dog harness, but it will hold and not break away with the slightest tug. They come in all sorts of fun colors. You might want to cut off the Petco tag

or you probably will get some dirty looks!
Best to practice before going. Just let the kid try on the harness around the house to get used to it, then take them on short trips to get the feel of it. For those who don't like it, just ignore them. Actually people that "matter' like security, police, cms, etc., have always approved when I used them. Too much can happen in a short time to a child. If someone does say something, you can always pretend you don't speak English or use sign language
