 You've got an unsecured rooftop 500 feet away from the president. An easy shot for a 12-year-old with a .22 trying to shoot squirrels. And you just give a guy a clear line of sight to Trump. At least if you were to put something there to block the line of sight, he doesn't see President Trump. And he's harder to hit. Not that he can't. If you put up some campaign poster or something, you still shoot through it. But at least there's a visual obstacle. You did nothing.