Magnetic holds for the pannier smugglers box.
HF rare magnets recessed into a 3/8" wide piece of plastic I had laying around. Backside cover in two sided tape and stuck to the pannier wall.
Rare earth magnets recessed and set into a dab of JB weld in the 1/4" luan smuggler box lid. Make sure you get all the magnets oriented properly or you have them pushing away instead of attracting to one another.
Lid now stays put when nothing is on top of it to hold it down and the stuff in the bottom of the pannier is protected/isolated from whatever you put on top.