I noticed the "checking ID with a light" thing at LAX this weekend as well. I was in the elite/F line in T4 (AA), and they scrutinized each passenger's ID with a UV light. They looked at mine for maybe 10 seconds, but they took about a full minute to examine his. We both have NY drivers licenses. They barely glanced at the boarding passes.

If this is a new procedure, they aren't following it at JFK. If this is a wonky LAX procedure, I'm sure the TSA blog will clear it right up!