The selling of military surplus has been going on for mmm years. At least from my knowledge early 1900's, considering firearms and many other things. Now there is a reciprocity agreement on many but not all things. The States have to abide by the Federal Constitution for many things, I will pick the 5th and 14 amendments, though I will not disanimate.
Inside of the state that you reside, the laws may be defined differently than other states. But the other state has the right to write, define the laws as they want. That is why attorneys will have their trials moved to a more client friendly State if they can.
In the atmosphere of endless litigation lawsuits, many entities now have to protect themselves by stating that "Johnny Bob" cannot use the surplus knife for cutting in the "State of Denial" because of the need that someone will sue because they cut themselves with the surplus knife sold by the "chain of custody". Which means that the lawsuit will include everybody, entity because someone cut themselves in the "State of Denial" and include the "chain of custody".
What a crock that because of some lawsuit, phobia, settlement, or it doesn't comply with some goofy pollution law, California, that all the other good decent law abiding people can not acquire and use the surplus equipment for whatever they like.
Just imagine that the Army cannot use their 5 ton in California because it doesn't comply with their pollution control format. OK California you are on your own. That is what we are getting to but that is the States right.