Guising requires those going door to door to perform a song or poem .
Guising requires those going door-to-door to perform a song or poem without any jocular threat , and according to one BBC journalist , in the 1980s `` trick or treat '' was still often viewed as an exotic and not particularly welcome import , with the BBC referring to it as `` the Japanese knotweed of festivals '' and `` making demands with menaces '' .