My last flight out of my small regional home airport, I only showed my driver's license to the agent. Had my boarding pass at the ready but I don't recall showing it. On my return from Las Vegas to home, again in the Pre Check line, I only showed my DL.

Interesting that anyone would go to the trouble of photoshopping a pre-check mark on a boarding pass. It is so easy to obtain PC, I can only assume they are up to no good to photoshop the pass.