It's the same type of accusation, without any proof and just based on assumption. My LS has killed Ulli within the last month without anyone else in the room, no CC at all. It happens, stop acting like they're saying they just magically get the stones to appear in their inventory. We also don't camp every hour of the day, so there's likely more times with very little if any CC.
Honestly I'd be stunned if they hadn't bought some from RMT, but until you can actually prove every level 1 mule in BD is a RMT mule; you have no proof of anything.