It's not always easy to find the landowner when houses are so few and far between. We used to wild camp a lot when the children were younger, often high up in the Corrieyairack pass (now blocked off I believe). Never did find out if there was a single owner, or several, or who they were. I don't think that anyone objects as long as the area is left as it's found, with no litter or faeces visible. Not everyone is clean and tidy though, so you have to make a judgement.
We have only a few acres, so it's fairly obvious who owns what, and we do sometimes get campers wanting to stay the night. So far they have all been great, and we still keep in touch with some, especially one couple doing a world tour in a Landrover ingeniously converted into self sufficient accommodation, who send us reports from all their trips. We prefer campers who don't need to use our facilities ie they have their own, not nipping behind a hedge, and who understand about livestock and gates.