I did too, was real fun.I 'high fived' dozens of kids. Its great to connect(not literally) with the supporting crowds. Imagine if folk tossed abuse because of the closed roads?
What wound me up though was seeing the High-5 gel sachets and banana skins (and water bottles strangely!) thrown on the ground by riders. There is absolutely no excuse for that. All my rubbish went into my pockets until I got to a feed station and the bins. Do some of these riders really think they are pros?!? These few gives all cyclists a bad name.