I personally think the answer to this concern is just semantics.

If Fed asks you if you're flying for economic crop evaluation you say NO. Just looking. They surely don't have the need to probe further, unless you just landed in the whitehouse back yard.

I haven't heard of anyone being punished for looking at their own fields. I think the Feds have bigger fish to hunt. But, if you hang a sign on the side of your pickup that says "Call XXXX for drone scouting" now you're inviting further scrutiny.

FAA has had to judge the fine line for many years for commercial activities vs private flying. This was in conventional aviation.