There are two things here that I think can go a long way in promoting and keeping this unique sofa.

1. It is passed security, so hopefully all of the money spent on preventing a device/bomb to get through security will work. If not, then that leads me to...

2. It is clear that people who commit such acts have no problem giving up their life. So, why would they leave a bag unattended? Granted, such a person or group would have to probably target Sweden and I am not up-to-date on what groups do target Sweden or what such a person/group's mentality is on self sacrifice.