YOur bagtag has your record locator which gives access to your PNR. The fear that the people can then find out that you are out of town and rob your house is unfounded. They can already do this if that was the game by just looking at your bag tag and not opening your bag.

This additional piece of advice is in case your external tag falls off somehow. No way to then match it to your itin or even your PNR, or easily match it with your lost luggage claim with 100% certanty.

While I am one for protcting my own privacy, checking a bag gives UA and the TSA rights to enter your bag. The data on the tag would give them all the same access as what is inside on a prined itin. (I know I am repeating, just trying to make it clear.) This extra step it in case your external stuff falls off. I guess if you fear that in the 1:10000 chance that your external tag falls off, and they need to go into your bag to track you down, and that person happens to be looking for houses to case, you have a legitamate concern. I'm worried about getting struck by lightening too, so I refuse to carry an umbrella in pouring rain. Guess what, it works...I have never been struck....but I sure get my suits wet alot. Mayabe I should take the risk and buy an umbrella...maybe you should take the risk too.