DD has been to big London marches. Loves it because we go to a museum after and she gets her photo taken. I've never been to a union march that had any issues. I always stand on outside she has to hold my hand so if anything happened I could get her out quickly ( I used to piggyback her a lot) I write my mobile number on her arm and she knows the drill. We get separated go to the police and show ur arm. I always know the route, more so we can easily leave if tired. Lots of snacks and drinks. She has a great time.