Not only is it exceedingly reasonable, google has a history of exactly this type of play. 2 examples: they offered "free 411" to train their voice recognition,

Not only is it exceedingly reasonable, google has a history of exactly this type of play. 2 examples: they offered "free 411" to train their voice recognition, and they used captchaa first to decode books, and now to train computer vision algos. The theory offered is superbly likely IMO.