By the time of that last one during the G8 Summit at Gleneagles, police cameras were being trained on every face walking by and press photographers kneeling in the street to get a dramatic cover shot of protesters in Edinburgh had no immunity when it came to a riot-shield charge. Somehow, holding political principles and wanting to voice them in public had become something to be viewed with suspicion or outright hostility.
None of these events was a life-or-death affair for me, although they were often exactly that for those in whose name we marched. I wasn't likely to suffer by sticking my head above the parapet for an afternoon. The same couldn't be said for those who campaigned for civil rights in the 1960s, as was underlined when Martin Luther King And The March On Washington (BBC Two, Wednesday, 9pm) was broadcast 50 years to the day after that iconic "I have a dream" speech at the Lincoln Memorial.
This was, by its nature, a television history programme. Talking heads relived their first-hand memories of the era, archive footage visualised those memories for today's viewers, and a narrative, read by Denzel Washington, drew the chronology together. But this is not history that is so familiar it doesn't need to be told again and again; neither is it history that is so remote its subject doesn't remain relevant now. There were, however, a few things that made this particular documentary carry more force than usual.
First was the anniversary date of the broadcast. Second was the fact that some of the most horrific images we were watching in our living rooms in 2013 - water cannons turned on black children in Alabama, police dogs set on their parents - had been seen by Americans watching in their living rooms in 1963, helping to turn the country's moral indignation against segregationists such as Bull Connor and George Wallace. Third was the way that the same stretches of road were repeated on screen in black-and-white from back then and in colour from now. Past and present suddenly were not so far apart.
The documentary followed key events through the early months of 1963, with a focus on Birmingham, Alabama; it pushed on through the week-by-week, then day-by-day preparations for the all-important march on America's capital city; it conveyed some of the momentum and excitement of August 28 itself by taking us hour by hour through music turns by Joan Baez, Bob Dylan and Mahalia Jackson, on to the speech itself. I wish the programme had then broadcast Dr King's words in their full 17-minute glory, from "five score years ago" to "free at last". Excerpts had to suffice.
The tragic next chapter of Dr King's story was available over on another channel afterwards in MLK: The Assassination Tapes (BBC Four, Wednesday, 10pm), but I felt it more appropriate to linger on a speech that seemed to come from the pulpit as much as from politics. It put pressure on President Kennedy to push through the Civil Rights Act of 1964 and it changed history through words of peace, not war or hatred. And that truly is something worth marching for.