Most of the cars I see with the "do not touch" signs around my area are the OLD ones, from about the 50 to early 70's. As for me my son has had quite a few conversations about watching him self around the cars at shows. I was even vindicated by one viper driver who saw him with a water bottle on an lanyard and asked him to be careful. I would think most parents would have the same conservation. As for the older "can read" crowd most would not touch unless they just don't care much and then they will touch anyway.
2013 LT2/RS, Crystal Red Metallic, TAZ Jr.
2016 H-D Ultra Classic, Black Fire Purple, (PPE)
2015 H-D Street Glide, Superior Blue. (Old Blue) Traded
2012 Big Horn, RAM, Crew Cab, SLT, Dark Cherry Red Pearl (Betty Boop)
1998 Honda Accord 2d, daily driver.