I've had agents tell me they no longer tagged 1P/1K luggage with the red tags (SNA), others put the tag on my bag with a little prompting, and still others automatically put the tags on. Likewise, I expect luggage handlers to run the gamut. i.e. If there is inconsistent training/handling by one group of staff, then why expect consistency from another group.

Offloading luggage from an aircraft, I expect, is a thankless task, made even more-so at a struggling airline.
So, when traveling in the US, don't check, carry-on.....