Is it possible you're thinking about carry-on as opposed to checked luggage? I don't see the connection between your boarding pass and checked luggage which is why I'm asking.

I check tags for two primary reasons:

1) To make sure that it is the correct tag for the airline I'm screening for. We have checked baggage pods located in close proximity and passengers sometimes come to the wrong pod. So I sometimes have to direct them to the correct screening pod.

2) To note the flight times. When we're busy, I have to make sure that the earliest flights are screened first so that they are loaded on the plane on time. Our goal is to have the bags back in the airlines' hands no later than 30 minutes prior to scheduled departure times. The airlines agree to put late tags on bags checked in within this 30 minute window. Since TSA is financially liable for any missed bags, I take the extra measure of marking the times on the tag itself of when I received the bag whenever they are within the 30 minute window but don't have a late tag attached.

The problem with markers is that anyone can use one to mark a tag unless we go to a color code system. For example, today we'll use red, tomorrow blue, etc. The problem here is that there is always 10% that don't get the word or will post the day's color code somewhere where everyone can see it which defeats the purpose of having a code. TSA tags are much easier. Airline baggage personnel know to notify their supervisor immediately if they don't see one on a bag . It's simple.

What I object to is TSA's obsession with uniformity by spending additional money to have these cool-looking holographic TSA stickers when the plain Jane ones we currently have suffice.