A quick-and-dirty way of
identifying solutions that don't obey it, perhaps. However, according to Wikipedia, the broadcast flag hasn't been made a legal requirement yet, so the "flushing out" may run the other way: consumers migrating from flag-compliant solutions to non-compliant ones. The content companies are running the risk of consumer activism by "testing the water" in this manner.
http://en.wikipedia.org/wiki/Broadcast_flag