This will only work sometimes. Most cheaters implement an "Anti-ScreenShot" function within their hacks.
What they do is hook the function that PB uses to force a screenshot and read when it is being used by PB. The moment PB Accesses the function to force a screenshot, the cheaters program(hack) knows and automatically disables all visual hacks for a few seconds, then re-enables them.
So unfortunately, unless the cheater is in-experienced enough to run in PB servers with a hack that does not check for Screenshot captures, its not going to capture the real threats(the experienced hackers that are getting away with by playing in a less Obvious manner).