The police and rangers gave us the impression that it was a permit issue. If only I had a permit everything would be dandy. But according to the code they referenced, Code 36 CFR 7.96, it seems our set up may not have required a permit. The code reads:
(i) Demonstrations involving 25 persons or fewer may be held without a permit…(E) Individuals or groups of 25 persons or fewer demonstrating under the small group permit exemption of paragraph (g)(2)(i) of this section are not allowed to erect temporary structures other than small lecterns or speakers’ platforms. This provision does not restrict the use of portable signs or banners.
Naturally, whether the banners count as temporary structures is debatable. But regardless, the truth is that what made the banners illegal had nothing to do with permits.