If I’m not being paid cash for my location data, I’m not going to be excited to help Foursquare collect it, whether it's anonymous or not. Paying me in contextually-relevant advertisements and recommendations (cough exposure) will never be enough.
No. The flat rate forces them to pay me when they don’t earn revenue and screws me when they earn too much revenue. The content publication industry worked out residuals years ago. They’ll need to do the same to earn my trust, and thus my location data.