Scottish access legislation defines wild camping as being at least 100 metres from a public road (thereby excluding roadside campimg) and not near a building or in a garden, on a golf course or in a military base etc. - is lightweight, (ie stuff is carried on the back and not in a vehicle) is for one or two nights only and is in small groups. People in general - including wild campers have to respect the rights of others , including landowners rights to manage and use land, including hunting/shooting/agricultural management and have to act responsibly. Acting responsibly might well include being quiet, not lighting fires, not leaving a trace of occupation and not polluting streams, damaging wallks or fences, digging holes, or disturbing livestock, control of dogs and crapping responsibly. If they do not do this then they lose the right to be on the land at that time and can be required (not asked) to leave.
Landowners also have responsibilities not to be unreasonable in the way they manage the land - ie in a way which would discourage use.
In theory you can wild camp on agricultural land without explicit permission but in practise most of that kind of land just isnt suitable for camping (eg its full of cow muck, oil seed rape, turnips etc)) - and wild camping generally takes place in the places where you'd expect it - ie in the hills. There are one or two popular places such as Derry Lodge, but this has been encouraged by NTS by the exclusion of vehicles further into the Cairngorms by the destruction of landrover tracks in order to make the Cairngorms just that bit more remote.
Mass wild camping at honey pots near to big population centres (in equivalence to the Peak or Yorkshire dales) doesnt take place - for instance, you wont see idiots in their red tent cities on the shores of Loch Lomond or Loch Lubnaig. You will see lots of roadside camping eg around Glen Shee, but this isnt "legal" and these peeps generally leave litter, crap in the burn, light fires and let their dogs worry sheep..... The petition has nothing to do with these people or people who travel as a lifestyle.
The petition is also closed so whatever is said in this thread won't affect it in any way - although the campaign to change the law is still in its infancy and its useful for people to have the debate.
Phew....