In the last century, when I last worked Lacey Act violations, it would come to the forefront when the illegally taken wildlife had crossed a state or federal boundary.

It could be argued that crossing a reservation boundary commits the Federal violation even within the state. Same for crossing a BLM, NP, or USFS boundary. An in-state violation is a bit of a reach and probably not too many Federal prosecutors would go down that road. When crossing a state or international boundary, that becomes a stronger case. Even better when multiple states are crossed as each would/could add to the progression of the case.

We did a lot of interstate joint state/federal check stations. Most states have what could be termed a "mini-Lacey" act where the possession of wildlife, taken illegally in another state, is illegal in the state where the violation was discovered. I have a fond memory of a check station on I-70 in Nebraska one year. Generally speaking, the violation was handled by the host state, in this case NE. The suspect had taken a deer illegally in UT, passed through CO, and hit the check station in NE. Turned out it was a UT officer canine team that detected the deer hidden in the trailer. The violator was advised that he had committed violations in UT, CO (possession and transportation across state lines), NE (same as CO), and then was advised of his options - NE, CO, UT or a Lacey Act. He lit up like a marlin hitting a bait and told us in no uncertain terms that if he was home in Texas he wouldn't be treated in such a manner. The TX officer assigned to the check station (we tried to bring in officers from surrounding states where hunting season were going on or just ending plus an invitation was extended to officers from destination states where the hunters lived),who had listened to the whole discussion then stepped up, identified himself as a TX warden and kindly said something to the effect of "Son, you would have the same problems in TX, now which agency would you like to deal with." As I recall, the NE ticket was chosen because it was the lowest fine amount. The deer was seized, went to a local food bank, and the violator went on down the road.