At a regatta over the weekend, Beachcats were sharing a course with some small monohulls (Flying Scots, Windmills, 420's). The SI's stated that there would be two windward marks, the inner mark (for the monos) would be a RED tetraheydran (sp?), and the outer mark would be a YELLOW tetraheydan. On day one of the regatta this was correct on the water. However, on day two, the mark boat mixed up the marks and put the YELLOW mark inside, and the RED mark outside. Going up the first leg (really light air) we found ourselves behind and contemplated rounding the YELLOW mark to gain advantage on the boats that were still sailing upwind to the RED mark. Of course, we opted to follow and round the mark that was in the proper location even though it was the wrong color. IF we had chosen to round the YELLOW mark, would we have sailed the proper course?