You’re 100% correct. There have been several rulings on the ‘knock & talk concept.
Without a warrant, or reasonable cause to believe there is active criminal activity, an occupant of a private residence is not required to open the door or speak to them.
Absent a notification from the state that an offender has not registered, they have no probable cause to obtain a warrant or conduct an investigation. The fact that an rso chooses to exercise 4th amendment rights does not constitute cause for anything.
Of course, getting a warrant from a friendly local judge is probably a piece of cake.
I’m like to come up with a method that would unite rso’s across the country to exercise that right and throw a constitutional monkey wrench into these compliance checks.
They don’t check on murderers, thieves, assault, (domestic or otherwise), or any other type of crime.
I think it provides food for thought that a registry is CLEARLY a Bill of Attainder.