If you are looking to get through security to complete a shop, it's not going to happen unless you are an airport or airline employee. Security is tight and even employees cannot use their access badge for personal reasons. If they do they can lose their access and also receive a hefty fine from TSA.
Your lunch is your own time but specific companies may have policies on what you can do on company time.
Bottom line, it's hard for "outsiders" to do airport shops. One of the exceptions that I have seen in my travels is Denver airport where a lot of the shops are outside of security.
I found discussion on getting badged but nothing specific. There seems to be a company that will get you an airport badge but the company was not named.
For those of you who work with the invitation only company who has airport shops, what say you?
I am not too worried about being badged, been down that road before. They pay for it and provide decent pay for the time it takes to go through the process.
OK, I know which company you mean now. They were very nice. Reasonable fees. You really need to know the airport. There's no time for mistakes. You have to go shop to shop in a logical order or you can't finish in the time frame. Filling out their reports is easy. I have never had one come back to me.
There are several MSC's that specialize in doing shops at airports. If you sign on with them, you can go through a security clearance with them and get "badged" for the airport. This allows you to go through security without a ticket and shop the various retail locations in the airport. I do not believe that any of these companies use the iSS platform...
I have never personally done this as I have no interest walking around an airport if I am not actually going to fly somewhere, but there are shoppers who do quite a few of these shops. Off the top of my head, I don't know the names of these companies, but I do get periodic emails from therm.