Think about the physical layout of the venue and consider whether it is likely in this specific case, before spreading FUD.
Now, the attempt on Trump's life was pretty easy to compute because we knew the exact location of the shooter and know that the 0.22 bullet hit Trump's right ear at a specific spot. And with possibly hundreds of not only cellphone cameras, but multiple broadcast quality cameras operating when Trump was hit, it was not hard to figure out the trajectory of the bullets fired.