A marketing firm has been criticized for using local homeless people as wireless transmitters at the massive music, film, and technology conference South by Southwest in Austin, Tex., according to The New York Times.

In what it called a “charitable experiment,” BBH Labs gave donations to 13 residents of an Austin shelter in exchange for their being equipped with mobile Wi-Fi devices to enable Internet access in densely packed areas of SXSW, as the event is commonly known. The participants were paid $20 a day and were allowed to keep whatever gifts they received from conference-goers.

Tech bloggers and commenters on the BBH Labs Web site widely derided the arrangement, which was due to end Monday, as exploitative and thoughtless.

Saneel Radia of BBH Labs said the effort was based on the model of homeless vendors in many cities selling newspapers on the street and was intended “to raise awareness by giving homeless people a way to engage with mainstream society and talk to people.”

Some of the homeless participants and officials of Front Steps, the participating shelter, defended the project. “It’s an employment opportunity, regardless of who is offering it,” said Mitchell Gibbs, the shelter’s director of development.