It is possible. It's easy for people to be mislead when they see the bettas in small unheated containers.All of other fish who require heated water and larger room are in bigger tanks, so if they required that then why aren't theythen ? you know..so it is easy for people to be mislead into believing they don't need
that for that reason...Unfortunately, a lot of petstores workers don't know much more than the people who walk by and ask them questions about the bettas. (that is not always the case though..some people..a very small number do know about betta care)
in any case...
This is why it is important for us to do our own research on any pet we bring home..and not rely on one persons at the petstores information.That is with any pet though..not just fish.
I also think they need to get rid of the care information on the side of the plastic containers they come in...most of the time it is awfully wrong.
I like this one petstore near my house..They put some of the bettas in the bigger tanks with the other fish that are somewhat compatible..they always have a betta in with their cory cat tank.