If I was Highway Patrol, I would do all the speed trap stuff too. Let's face it, all Highway Patrol really does is write tickets; they rarely do any real policework. That shit probably gets boring day after day, so I would get creative and use whatever tactics I could to get speeders. I have no beef with that.
I wouldn't write a ticket for a 72 in a 65 or stupid BS like that, but I would have no problem hiding or setting up a "trap" to catch some idiots going 90. If that's my job, I'm gonna go all out. Fuck sitting around in plain sight all day.