I dont know Spints process, but what we usually do is as part of a routine survey we ask people if they would be interested in participating in a focus group for some compensation for their time. If they want to, they leave their contact info.
Of the 1,000 people who say yes, maybe 20 actually agree to show up at the required date and time.
They then sign off on waivers concerning their rights to privacy and such.
Obviously having a room full of cameras completely changes the dynamic vs a fully private and anonymous discussion. The filmed conversation is probably not valuable at all.