There is a "tent" off-trail before you get to Bighorn. Ranger residence. Do not distrub.
You see rangers checking overnight permits at Outpost Camp. They come out of nowhere. Friendly chat at first, but be sure you are trail legal.
Rangers know the "shortcuts" on the trail while minimizing impact on the vegetation. Yes, they practice what they preach. They come out from out of nowhere.
You will see them at the Lone Pine Lake junction. It doesn't hurt to stop and chat with them. You will see them on the trail between John Muir Junction and the summit, but they are not the Inyo variety. Rangers work closely no matter where they are from.