Adult or cowardly thing to do?

My little brother (age 6), who I hadn't seen in 3 weeks (since the 4th of July weekend), and I (male, 24) were at a Ross discount store in Visalia, California. We saw 2 beanbag-type chairs (for sale) and decided to sit down and rest and also look out for our mother who had disappeared from sight. My phone's battery was too low to make a call.

My brother was concentrated on his iPad mini and I was kind of people-watching. After a few minutes of sitting down, some teenage-looking female walked by and noticed us and stopped and told us "you cannot sit there." I saw my little brother sit upright (whereas before he was leaning back) after hearing her. I could only see the back of my brother's head but I imagined he must've had a surprised look on his face with his eyebrows raised, eyes and maybe mouth open.

For a second or two, I thought about how to react. I then put my hand on my brother's back as I began to get up and told him "let's go."

This happened 2 days ago and I still wonder whether I did the "adult" thing by not arguing, not asking questions, not making a big deal, or if that was the cowardly way to react.

I automatically assumed she was a store employee, but I later realized I wasn't sure, because less than 10 minutes after that, after walking around the store a little more, my brother and I walked outside of the store and there she was on the phone and walking away slowly.

I wonder whether I was really setting a good example or if it was a bad example for my bro.

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