It’s not that simple – plenty of dog walking areas are not woodland but for example open grassland where just because it’s not on a path doesn’t mean it won’t get stood on. Plus kids like to play in woodland, hide and seek in bushes, and so on. Just cos’ it’s out of sight doesn’t make the problem go away.
A second aspect is that some areas have highly specific and fragile soil ecologies, and the high N and P contents of dog waste change that balance. Additionally, residual levels of eg worming or flea treatments can be sufficient to kill invertebrates or lizards that feed on it.
http://www.frp.org.uk/pdf/frp/2_Acid_grassland_July_2004.pdf
Lastly – military areas are blighted by this, where owners kick their dogshit into a bush only for some poor soldier to then dive on it and spend the next 3 days covered in dog mess.
I know not all areas are susceptible to all these situations, but having different rules for different areas causes confusion and where that exists, excuses. The rule should be simple, if you have a dog you clear up after it and you deal with it until it’s in a bin. Leaving a bag ‘to collect later’ should carry the same penalty as not picking it up.
I’m a dog owner myself, and it’s part of the territory to me. And excuses like not wanting to carry it for miles or hours after just don’t wash, sorry. You knew the rules when you got the dog, double bag it and deal with it.