Would you really? My gut feeling tells me that's not the case for most people for privacy or ethical reasons. Just because those people are poor, we expect them to have lower privacy or ethical standards.
The link you posted has the following example, I think you're referring to that
> BBH Labs was an exception – they outfitted 13 homeless volunteers with WiFi hotspots and asked them to offer WiFi to SXSW attendees in exchange for donations. In return, they would be paid $20 a day plus whatever attendees gave in donations.
That's completely different. Offering Wifi has zero long term effects. It's providing people with a "business opportunity" that wouldn't have access to it otherwise. Giving someone 5 bucks for their face picture (or other biometrics) is totally different and has long term negative effects.