Elite: Dangerous PvE - Mobius

Before I continue, I must stress that my drones were stealing from NPCs and not real life commanders.

But yeah. I'd just finished mining this particular rock when this NPC mining crew jump in and start mining it. Before I realised it, my collector drone had scurried over there and started collecting the fragments they were mining. Considering I had depleted the asteroid, could this be considered an exploit?

Also, it there any way I can reprimand my remaining drones and make sure they keep their light fingered habits to themselves?

The resources of an Asteroid are always per ship, this one of the benefits of mining in wings and not an exploit. Telling your limpets what to pick and what not pick up is not possible, the only thing you can do is downgrade the collector limpet controller to D. This results in a small loss of limpet live time, but the main benefit is that the search radius gets smaller, causing your limpets not to stray so much.