I have used the Alaska Air print your own baggage tag off the QR code, and it works well. On the other hand, my Wife would never figure it out. And she is significantly smarter than me.
The issue with the Alaska Air prints your own baggage tag is the "free for all" after the tag is printed. A line gets formed to drop off the bag, but the line goes through a gauntlet of kiosks. So, if you print you tag at the "end of the row of kiosks", the PAX printing their tags at the front of the kiosks are oblivious to the line and keep cutting the line, without realizing that is what they are doing.