Does adding a google account to phone increase data charges? I've written an app that uses google push notifications to install upgrades. The problem is that certain companies that my app is rolled out to, have phones that are running Android 2.3.6. This means that for the push notification to work, a google account must be present on the phone.

One customer only has a limited data plan for his employees and is reluctant to assign a google account to his employee's phone because of the potential data charges. 

Would assigning a Google account to a phone incur potential data charges on the phone? 

He has mentioned things like emails, spam, links to YouTube. All of these worry him as he thinks the employee may use things outside company purpose.

Thanks
Yes, assigning a Google account to a phone would incur data charges UNLESS syncing is disabled as it will regularly sync calendars, email, etc.  Even so, other data related services may come into play (eg, Play store app update checking &amp; downloading).