Just about to watch this on iplayer. I do recall watching a panorama or similar bbc documentary along similar lines about 2 years ago. It followed a group of what appeared to be; grumpy, aged 65+ ramblers/ residents, who genuinely looked like they were enjoying causing trouble, creating a committee, and having something to moan about, VS an assortment of trail bike riders and 4x4 drivers.
I'm not a rambler, but I'm a regular fell runner, and hill walker, and spend alot of time in the hills. I also studied agriculture and worked in farming for a few years, so have strong ties with the land and the countryside, but I have yet to see a convincing argument for why motor vehicles are dramatically worse for byways than other forms of transport.
IF there was reliable evidence to show that the effect 4x4s and motorbikes have on byways was greater than the total effect of other transport methods, eg, pushbikes, walking, horses etc. then I would be more inclined to agree that measures should be taken to limit motorized transport, but I would still argue that alot (certainly not all), of the motorized transport users are far more concerned about the maintenance and upkeep of the countries byways, than any rambler or cyclist that I have ever met.
Residents who live near byways don't have a leg to stand on. If they don't like the fact that people are choosing to use a right of way near their house, they should A. Remember that they were well aware of the fact it could be used when they purchased the property, or B. Accept that they were an idiot not to realize that they were buying a properly next to a right of way.
Finally I think there is a strong argument to say that having byways open to motorized vehicles is an important way that disabled people can see the countryside, not from the comfort of smooth tarmac. I'm sure that to wheelchair users who cannot use footpaths, and who wish to see more remote countryside than can be experienced from a mountain pass, a greenlane offers an opportunity to explore the outdoors and get to remote places open to all members of the public.
The greenlane debate is one big can of worms, but those opposed to 4x4s and motorbikes I think are often doing it for the wrong reasons, and without a full knowledge of the matter.