Ahh... Drawing on demand is quite a different thing. If someone want's a drawing and with me it's usually something graphic. We can talk terms. I convert hard drawings to digital and add water marks and send the files to them electronic. Digital drawings I save the progress of the piece but what I send to them still has a watermark. Watermark is not lifted until I see the green. Still if to court I must go, Than I still have the hard copy or an extensive file to show the Judge.
Doing art for other people can drain creativity from us. Just because we enjoy it doesn't mean they can have it for free. There are tradesmen out there who absolutely love their jobs. But we would have the gull to ask one of them (such as a plumber or an electrician) to come to or house and do work for free just because they love their jobs.