Not really. I personally think it's wrong, what's the point of following if you're just gonna unfollow.
I would be frustrated as well, I know that once I went to click follow for someone that I was already following and ended up unfollowing them. I followed them back again of course, maybe something like that happened in the situation?
This is not cool at all... Just to get fan following they follow and then when you follow back they cleverly unfollow.. such cheats !! Might sound rude but it is bad!