I believe sooner or later, there will be a market for those private drone owners/builders to accept “special” missions of almost every type to spy, visualize, monitor things we may not even imagine right now.
They will be able to sneak into everything and every airspace, collect every type of data, to be sold privately and even out of control of authorities.
Say an small drone with the least possible RADAR signature follows a series of way points, simply collects data and because it has no communications it also can not be easily traced or seen, then comes back home with a treasure of data to be sold, used or abused.
It is inevitable, it will happen. Not people not lawyers and not even governments can control this.