Well, at least my luggage was... On my flight from Hong Kong to Tokyo, my checked luggage was tagged with RFID tags, presumable to track the bags through the luggage handling system and verify bags went with people.
What's interesting to me is that the RFID itself is but the tiny spec in the center of the tag. Most of the tape you see in the picture is simply the antenna laid out as a metal strip on the tape. I would presume with this much antenna, the tag could be read at a sizable distance.
This is the first time that I've noticed such a tag, but I wouldn't be surprised if this technology was incorporated into the typical baggage tag added to your bags when you check in. In fact, I'm surprised that it wasn't done that way in Hong Kong. Perhaps by taping it to the bag, the tag & antenna are more likely to stay flat rather than getting bent or otherwise deformed as it hangs off a baggage handle.