A few opinions here https://www.google.co.uk/search?q=z&rls=com.microsoft:en-GB:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7PRFA_en&gfe_rd=cr&ei=mBTRU_ybBYrY8geGhYCgDg&gws_rd=ssl#q=pointless%2C+100+people+asked&rls=com.microsoft:en-GB:IE-SearchBox
I think Richard Osman has said that the 100 people answer on the Internet, and they don't know they are being asked for Pointless. It's not something you can apply to do.
I was in the audience a couple of months ago and we asked how it was done. It's all done via email or over the interent and the people dont know what they are answering questions for. i don't know how you get involved.