I love self-righteous guys who take the opportunity to lecture someone. I see credentialed pros get run over all the time at bball and football games - it is the nature of the beast.
In general you learn to stay back from the sidelines, although that doesn't always guarantee not getting clobbered. That's why a lot of sports guys shoot with both eyes open - to cut down on the tunnel vision effect.
Current: 5DM3, 6D, 8mm fish, 24-105/4IS, 35/2IS, 70-200/2.8IS, 85/1.8, 100-400/IS v1, lensbaby composer with edge 80, 580's and AB800's
Formerly: 80D, 7D, 300D, 5D, 5DM2, 20D, 50D, 1DM2, 17-55IS, 24-70/2.8, 28-135IS, 40/2.8, 50/1.8, 50/1.4, 70-200/4IS, 70-300IS, 70-200/2.8, 100 macro, 400/5.6, tammy 17-50 and 28-75, sigma 50 macro & 100-300