Same here - usually state ID + BP, for a longtime a passport (the state ID took a few months to materialise). On one occasion using Pre, the screener quickly thumbed through the passport (presumably looking for any hidden objects, they weren't reading the pages).

I've done the same in non-pre lines, they don't mind me holding a passport in my hand.

Note: my passport has an RFID chip, but no shielding. I think some countries now incorporate shielding into their passports, I'm not sure how that would affect metal detectors.