It can be a number of things, including stupidity. It can also be a desire for attention, a desire to get someone back for something they did, a desire to hide something (such as a trip they don't want people to know about), a desire to distract from something else, a desire to start her life over without her loved ones, etc, etc. There are endless motivations that could make someone do this, but most people think about the consequences (committing a crime, stirring people into a frenzy, heartbreak for family, wasting resources to name a few) and don't do it for those reasons. Carlee, unfortunately, didn't think or care about the consequences, IMO.