well yeah, that's against the point of "anonymity" ... you are feeding the app all the data it needs to fence you in.
By this logic every government gives a uniquely IDable device to its citizenry for engaging polls.
Besides ... if it was "important enough" to break, getting around geofencing etc. is a trivial/already solved part of this.
Depending on the importance of the poll, one could definitely apply these other requirements.