in app billing - How to track user statistic in android -

in app billing - How to track user statistic in android -

i'm looking solution info amount of bypassed premium purchases.

my actual approach in short: maintain track of usage when premium feature -used- , send info web server.

actually concept provides user grants "read business relationship information" permission. able receive android-id , gmail-account well. @ end hope useful info security issues, maybe hide in in-app-billing code, comparing info in wallet database.

my question:

i not sure if necessary collect these user info @ all. of know, here in federal republic of germany people in panic fast, when wants collect usage information.

i appreciate helpful information. regards , in advance.

android in-app-billing usage-statistics user-data