Host is testing out their own material and ideas. Sometimes i might play a track i've made that i'm not sure i'm even going to release. I may just want to see if there's any reaction on twitter (during the radio show) or the dancefloor. If there isn't much i may decide to completely scrap it and start over, or use a part of it for a future remix... If the host identifies it as one of their songs it get's ripped to youtube and becomes a topic of discussion "why didn't you release it?" "why did you change it so much" "why did you use part of your own track for a remix of that other track" and so on... keeping it ID reduces those questions and keeps things simple.