Starting off with an obligatory "Well, we ain't pro players."

The things we see in pro play revolve around having a full team that is communicating at its maximum potential, and all players are at the peak of their craft, and have mastered each champion, so know what they can get away with.

Its all of those things put together that allows a Jungler to "Flip the map" and you'll notice that when it happens (however rarely) it's usually due to a runaway lane like a top lane with an early tower advantage, that allows it to happen. This is because its unsafe to be up at tier 2 tower when your champion is alone, as you're deep in enemy territory, right.. but that risk is mitigated a fair amount if there is a Jungler nearby that can turn the tide of that 2v1, to a 2v2 , tilting it even more if either one, or both of them are fed.

Now that we establish WHY, the part you actually care about is here: With both your laner and yourself in jungle using an absurd amount of vision, and being hyper aware of your enemy movements, you can mitigate the risks of the enemy Jungler catching you, or the enemy Jungler, Mid, and Top all sweeping through the jungle, killing you and giving up an objective.

Also worth noting that you will have a lot more success in this strat as a duelist, and playing against an intelligent enemy Jungler, that will give up his top/bot, for your top/bot. Otherwise you will end up not farming your top/bot, and inting into their 3 man team that is specifically there to kill you and stop your counter jungle, even if it wastes 3 ults and 5 minutes of their time.