Signal Strength to control Unmanned Craft

There is a need more and more for automated delivery via robotic craft. For example:

The Progress supply ship, which blasted off from the Baikonur cosmodrome in Kazakhstan on Wednesday, arrived about eight minutes ahead of schedule and hooked up to the research outpost at 2:46 p.m. EST (1946 GMT), NASA's mission control in Houston said.
http://today.reuters.com/news/newsArticle.aspx?type=scienceNews

Think about that for a moment. When lifting off, ground control needs full control over the spacecraft. But when docking to the space station, the space station personnel need full control over it! So, at what point does one control switch to the other?

I say it should change with distance: the closer it is to a control point, the more strongly the controls at that point can control the unit. For example, as the craft is nearing the space station and a human operator in the spacestation sees it coming, his controls take over control of the ship long before it tries docking. This way the right speed, angle, position, and so forth can be guaranteed. Also, the most responsiveness - time lag with distance can be very harmful in time-dependent precise controlling of things, such as when docking one ship to another, far above earth. A half-second radio delay could yield horrible results, in a place where there's no room for error. Errors in this situation cost millions, if not billions, of dollars.

This would also work for remote-controlled cars on the road, which we definitely will have some day. The metal bumpers on the sides of mountain roads could have radio controls in them, with very close proximity priority; if a remote controlled car got too close to the side wall, the instructions from that side wall being transmitted by radio would temporarily take over control of the vehicle (or influence it), with the instruction "stay away from this point," or "go away from this line or plane". When the car is in the normal driving area, it's too far away from the side of the road for there to be any influence from that signal. But the closer it gets to the edge, the "stronger" that signal is perceived, so the more certain it is to have an affect in the car's decision of where to drive.

The worst-case would be that the vehicle becomes a bumper-car bouncing between one side wall and another, never hitting either; steering powerfully each time it nears one side, plunging it over towards the opposite side.

So - if you see that behavior in the first buggy models of robot taxis that come out, or whatever vehicle is first tested on our roads - you'll know where the idea came from. :)
(A good movie with this kind of robot taxi is one of my all-time favorite movies, Total Recall starring Arnold Schwarzenegger.