Microsoft Graph REST change notification resource data without encryption

Question

I am trying to get presence changes of a Microsoft user, using change notifications. According to the documentation, to include the value of the user presence (say, { availability: 'Busy', activity: 'InACall' }), I am required to send the parameter includeResourceData as true, in which case, I am also required to send a certificate and certificate id for encryption of resource data.

But as of what I observed so far, when I don't send the includeResourceData parameter at all, the change notifications still contain the resource data unencrypted. In such a case, is it advisable to keep using this resource data without requesting it explicitly and sending a certificate? Or is the resource data that I am receiving is temporary and it's possible that I won't receive it in future without sending a certificate and id for encryption?