Obviously, with the international space station you need to do some station keeping when you're falling into the atmosphere. However, I saw the following image showing the Halo orbit that the Deep Space Climate Observatory is in:

It seems like once it hits its stable exponentially unstable halo orbit, that the speed is between 0.15km/s and 0.05km/s. At what point would there be a red flag? Is there an easily calculable escape velocity for an orbit around a Lagrangian? What would scientists be looking for to alert them that they need to do corrections for such an orbit?