If there is Grey beings, they are bio- robotic drones pre-programmed for a purpose. Similar to a virus or worm sent to achieve its final objective. Whomever are the ones that are programming them, we will truly never know? They may be also sent with other types of beings that are programmed as well to complete the objective. Types may vary, thus humans that may interact with them will report this as an alien encounter. The tech. we will never comprehend even at the current level to date. Food for thought, notice that some nations military applications are using drone tech currently? This was a property perhaps that we configured to work easily via alien tech. at the simplest/beginning stages of those applications. Just observe the next stage, ground based pre-programmed tech. which is already in progress. I believe whomever is sending/programming these beings to interface with our planet, wants to know how we react to the initial programs/aliens sent. Regardless of the negatives that may occur, when sending out the drones they receive the up-link, no matter how many light years away it may be.