I am a thunderegg hunter for the most part. I just recently became fond of the Keokuk geodes when I purchased a collection of geodes from a widower of a Keokuk area collector. This collection was comprised primarily of whole geodes, and many geodes were cracked by the geode hunter.
Hunting thundereggs at most locations out west involves only the 'getting there' and the digging. These locations are on BLM (your land) or on established claims where a small fee is paid to dig.
The Keokuk geode locations are all on private land where permission to dig must be obtained. I have gained access to many of these locations, and I make a trip to these areas every spring before planting season.
Only a small amount of geodes can be dug/chiseled from each location. The shale is very enduring and the freezing and thawing action of the cold winter season will loosen up only a few geodes each year. The shale gets harder as the summer progresses and the geodes become impossible to get out. The Alvis mine in St. Francisville, Mo is mined by taking the shale off the top by a backhoe. This makes it 'easier' to get them out by having access to the tops of the geode. When the Warsaw formation containing the geodes is in a bluff, you only have access to the front of the geode making it more difficult or impossible to get out without breaking.
Sometimes when I get to one of my locations where I have exclusive permission, it has already been dug out by someone we call a 'claim jumper' out west. There will be no more, or very few, geodes to come out of that location for that year. I am screwed, and the landowner is screwed (I pay the landowners two dollars a pound). If you do the math: five average geodes at two dollars a pound equals fifty dollars. That is felony theft!
Most of the folks hunting geodes without permission rarely get a good geode. Someone before them has already dug and sorted out the hollows leaving only loose solids to be found. There are no geodes peeking out from the formations, they have all been dug. But for the other one percent of these robbers, the ones who know what they are doing... It takes only a few hours to dig out a locality and leave nothing but worthless solids for the folks coming after.
For all this rambling I want to make a point: Don't trespass! If you take geodes without permission, you are stealing.
I am going to write frankly about the 'navigational stream' controversy. In my opinion, it is great when folks float the Fox, Des Moines or Skunk rivers and play on the gravel bars and pick up the geodes laying about. It is not great if these same people wander up a small drainage or cross a fence. You deserve having your wonderful day ruined by the landowner who doesn't want you banging on his rocks. And they will ruin your outing. Obey the rules and try to be quiet (no hammers) so the landowner isn't even aware of you floating by. That isn't hard to do and you might see an eagle or deer or fox or beaver or blue herons or those giant soft shelled turtles.