To my knowledge (so this may not be entirely true ):
The VHS MacroVision copy protection is defined by adding bandwith and distorting the original signal. The tuners and scart of television sets can handle the extra content because their bandwith is much bigger than the tuner and scart of a VHS videorecorder.
Buena Vista (Disney) was one of the first to copy-protect their VHS tapes. You could easily rent a VHS, connect a 2nd recorder in between TV and 1st recorder and copy while you were watching. Not anymore thanks to Disney.
The disabling method of VHS Macrovision copy protection schematic has already been published in numerous electronics magazines. I'm sure your local Radio Schack can sell you a Macrovision remover for a few bucks.