Yes, you're right. Explain to me why zeteticism couldn't reasonably lead to the same conclusions? It seems that for such a question, formulating a hypothesis is completely unnecessary. Or maybe you could explain what purpose a hypothesis would serve, when the only thing you really need to do is question the store owner and perhaps some employees for an answer to the question.
The problem is, Zeteticism doesn't require any additional research. Zeteticism stops at "Because the store was sold out." The Scientific Method, however, essentially digs deeper.
Relating to the Earth, a Zetetic might say, "Hey, the Earth looks flat; it must be flat." Anyone following the Scientific Method, however, would ask (hypothesize) "Why does it look flat?" From there, they would do experiments, etc, and eventually find out that it looks flat because of perspective. It won't look curved until adequate altitude is reached.