Meaning of GPS criteria setting setCostAllowed on Android

I am trying to figure out the meaning of setCostAllowed() setting for GPS criteria. Android documentation says "Indicates whether the provider is allowed to incur monetary cost."

Who cares if provider is incurring any costs? I never seen a line on mobile bill that says "gps charges". Has anyone ever been charged for this?

If not, why not just set it always to 'true' and forget?

Ideally this is something I'd like to give the en开发者_如何学编程d user control over, however putting this option in application GUI may only raise more questions to which I don't myself have an answer. Does anyone have an explanation for this setting?

The reason for the setting is that not all mobile plans include an unlimited data package, thus customers are charged a per-use fee for data, which includes GPS data. So, it's necessary to ask users if it's okay to incur costs on their behalf for data that your application consumes (i.e.: give them the opportunity to opt-out).

The Criteria for requestLocationUpdates is used to choose the 'appropriate' provider depending on the parameters specified in the Criteria. Sometimes this may refer to having the NETWORK_PROVIDER which in-turn may result in a data connection having some cost incurred on the user.