Doesn't matter where you add the restriction. Some people have put plastic epoxy mixers into lines. Supposedly they do a great job. Haven't tried it myself.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk