I agree to an extent with knowing were you are at all times. I think a little help from landowner marking there land if they don't want people on there land would be good too. It would take away alot of guessing and confrontations. Signs and spraypaint are not hard. Plus it would mostly be done by a Ranch/farm hand or a kid.
On the other hand I've seen land owners run people off public land claiming it's theirs so there will be some posted public land. The farmers/ranchers will have to look at real property lines not what grandpa told them they owned when they were kids. That will be a problem for some.