But you could still just walk by the normal checkouts if you don’t have anything

Ah yeah, of course. I thought that was the same in the location of the article, but maybe I misunderstood and that's the main issue.

After re-reading it I'm still confused by this paragraph:

During my Monday visit, I purchased a kombucha and went through the check-out line without incident. (No high-tech gates block the exit if you go through the line like normal.) But for journalism’s sake, I then headed back into the store to try going out the new gate.