Unlike the menacing crowds that had smashed shop windows and destroyed property at previous G8 events, most of this year's protesting contingent were content to spend their time chanting, dancing and engaging in soil purification rituals.
Well first off the G8 summit was not held in Europe, that helps a lot. The anarchists and such don't have a lot of cash to travel. It also helps that America has one gun for every single man, woman, and child in the US. That tends to deter random acts of violence.
Also, since any method of traveling their would require the use of a multi-national corporations. Flights, boats, renting cars, and buying gas. So it would kinda been hypocritical in some extent at least, even buying a bike would require the use of a large business most likely.
Secondly, the weather was 90°F and it Feels Like 97°F. I played some softball and I have drank about a liter and half of water, it was hot and you don't protest when it is that hot.