Is it not ok to view the room then not rent it?

Hi, I'm in the process of looking for a place to rent in BKK, I have some places that I want to look into already and have scheduled the viewing with agents, but then I saw a post on fb group about am agent complaining that a customer come to view the room and then not renting it, which is a waist of time for them and the owner. So now I'm quite confused about this, since I'm new to BKK and don't know much about how the rental process works here.... Is it not a common thing here to look for different rooms then decide which is the best place to live in? I'm just afraid I might misunderstand the concept of "viewing" here🥲