You're observations are pretty much spot on.
Some of you might be interested in a bit more info about the Emert case, it's actually pretty interesting how the whole thing went down. The following details are quoted from the legal textbook Water Resource Management, Fifth Edition p. 461
"The record shows that on July 3, 1976, the defendants entered the Colorado River from public land to do a float trip downstream. The Colorado River flows westerly and bisects the ranch of the Ritschard Cattle Company. As it passes throught the ranch it varies in depth from 12" to several feet. The rafts on which the defendants floated were designed to draw five to six inches of water, and had leg holes through which the occupants could extend their legs into the water below the rafts. This enabled the defendants as they floated down the river to touch the bed of the river from time to time to control the rafts, avoid rocks and overhangs, and to stay in the main channel of the river. They touched the riverbed as it crossed the Ritschard ranch. The defendants did not, however, leave their rafts or encroach upon the shoreline or manks of the river or islands owned by the Ritschard Cattle Company.
Upon being notified that a party of floaters was approaching, Con Ritschard and his foreman extended a single strand of barbed wire across the river at the location of the Ritschard private bridge. The strand of barbed wire was from eight ot ten inches above the surface of the water and was placed in this position specifically to impede the defendants. Ritschard and his foreman remained on the bridge to tell defendants they were trespassing on private property. Defendants Taylor and Wilson were stopped at the bridge and told they were trespassing. They denied this and floated their rafts under the barbed wire and remained under the bridge for a period of time until defendant Emmert, and others in the rafting party caught up with them. Shortly, a deputy sheriff arrived and placed the defendants under arrest, and they were subsequently charged with third degree criminal trespass
The parties stipulated that the river is non-navigable and had not historically been used for commercial or trade purposes of any kind. However, the river had been used in the past by recreational floaters using rafts, tubes, kayaks and flat-bottomed boats, despite the express objection of the Ritschards. At the time of the incident, the river had been posted with no-trespassing signs.
Also, it was agreed that substantially all of the Ritschard ranch land was deeded land with no exclusion of the bed of the river, and that the area where the defendants were stopped was such an area, with the land on both sides of the river owned by the Ritschard Cattle Company"
David Emmert was not, and is not a lawyer, to my knowledge. He represented himself as a pro se defendant. Any lawyer worth his salt would have never agreed that to the stipulation that the river was non-navigable, and anyone who passed 6th grade history knows full well that the Colorado had in fact been used for commercial purposes, historically. Instead, Emmert chose to contend that his actions were lawful according to section 5, Article XVI of the Colorado Constitution, which reads: "The water of every natural stream, not heretofore appropriated, within the state of Colorado, is hereby declared to be the property of the public, and the same is dedicated to the use of the people of the state, subject to appropriation as hereinafter provided"
While the Emmert decision is not in fact, a law, it does represent the Colorado Supreme Court's interpretation of section 5, Article XVI, at that time. Many feel that the court interpreted the article incorrectly and that the current court might interpret it differently. I happen to be one of those folks, as were justices Groves and Carrigan, who dissented. In his dissent, Carrigan wrote: "The constitutional language in no way supports any intent to provide for exclusive private use of public waters" I couldn't agree more...