The coolest place I've ever shredded was on the edge of a cool waterfall at glacier national.

The bag eventually went over and I had to wade out into the freezing cold glacier melt at the bottom to retrieve it haha.
As for the other, I've never actually actually been kicked out out of anywhere, but me and some friends once had a circle going in the lobby type area of a Walmart until an employee asked us to stop. I also have had my bag confiscated for practicing clippers in the lunch line


