I haven't seen this out of the European airports I frequent.

Before September 11th at JFK, United used to put a huge, green "X-Ray Before Loading" tag on all international bags. (Domestic bags didn't have to be screened.)

It depends on the contract security agency and the airport. One of my bags still has a huge "Continental Security" tag from Buenos Aires. I get smiles from former Contintental employees at the airport.

Some airports, particularly in India, have a special tag for hand baggage as well.

For a long time, the ICTS personnel would put a small sticker on checked luggage--the same sticker used on the back of the passport and/or on the boarding card. But I haven't seen that in a long time. I imagine those stickers fell right off.

At Ben Gurion Airport, they have large tags that are essentially all bar codes. These are used for checked and hand luggage that has been selected for screening.

And, of course, the Hawaii Agricultural Inspection stickers remain in full force.

As technology improves, I imagine that stickers and tags will eventually fall by the wayside. They do seem like an anachronism.