This could be used for many companies, but let's say Tesla.
Say you rent a place and put a camera next to the Tesla factory/factories. As each truck delivering Teslas comes out, you count the number of trucks by later watching the camera recordings. If the number of trucks times the amount of Teslas on each truck per quarter misses estimates of Tesla sales, you short the stock before earnings reports, or vice versa.
Has anyone ever thought/done something like this?