They may not have been in prechek. In our several of my recent Airport Security Screening experiences even the non prechek lines have not done the no shoes and 311 Baggie drill. Since the Airport Security Screening authorities don't communicate process stuff "in the interest of safety," there is no way of knowing whether there has been a change in policy or if those Airport Security Screeners were lax and sloppy.
IIRC the 311 rule applies to prechek, it's just that the Baggie gets to stay in your carry on.