Individual small tents and how many, or a big family one?
For me wild camping is easy because I make a small footprint with my one man tent (soon to try out a Bivi) but also timing can be important. I do not try to pitch until at least dusk, by then hopefully everyone that might disturb me is tucked up indoors or down the pub. I don't cook whilst hiking so for me there is no fire. Depending on your tent size and/or space requirements you may have to make a personal judgement of taking a chance, or ask a farmer? Personally I would also suggest that you think about what time in the morning you will all be able to be 'up and doing and away'. Another consideration is, are you a noisy lot? Noise can attract undo attention. For me, I rise at the crack of dawn, I gather my stuff together and then walk on. I worry about food, shaving and so on, maybe up to two hours later when I've found a nice spot to have a break. Some people hang around their tent to prepare breakfast and so on before they decide to move on, or can sleep in for much longer than I can, its in these situations I think that you are likely to be discovered and are pushed into explaining yourself.