How do I get the IAP entitlements for a user that's not me?

So, I can get the local player's IAP entitlements via Oculus.Platform.IAP.GetViewerPurchases() , but how can I get the IAP entitlements for another player?

My use case is that I'm working on a PVP game with cosmetic IAP. If player A reports to player B that he's wearing a specific IAP cosmetic, I want player B to be able to verify that player A actually owns that IAP. This is to prevent player A from hacking and showing opponents that he has IAP that he doesn't actually have.

Maybe I could use the https://graph.oculus.com/12345/verify_entitlement server call, but I've been having trouble getting it to work, and I'm wondering if there's a more straightforward way to do it in Unity.