Is it safe to give away the APK?

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http://stackoverflow.com – I have paid app on Google Play Store. And some marketing team asking my APK for them to publish on their Store. Apparently they can reach out users which are not covered by Google such as China, etc. Another approach is they are selling a "Gift Card" which available on the ordinary stores, so they can reach offline users. Users then use this "Gift Card" to purchase the apps via their digital Store. 1st Question is Is it safe giving away the APK? I could see the risk of my APK being ripped of then the cracked version would be all over the sites. 2nd Question is what is the best approach the (HowTos)