I had no real understanding what responsibility was. By this I wasn't really aware that life wasn't a game. I WAS immortal. It is quite easy for me to understand that the youths just built one fantasy on another. Perhaps at the end they realized the error, maybe not.
People fantasize and day-dream all the time.
There are some relationships that young people get into that feed into each other in a negative way that could create a fantasy world. Again, this is the adult side. The parent needs to keep engaged with these young people and by doing that can be more likely to pull them out of that. At some point, adults need to say that something is not okay and goes outside a good boundary. They might not like to hear that, but it is the most important message you can give them.