When should preemptive pointers be sent?

[benStre]

Currently, an endpoint preemptively attaches pointer values to a DATEX message if a few conditions are met

1. The pointer action type is GET (not SET or INIT)
2. The DATEX message is not sent to the its own instance
3. The receiving endpoint is not yet a subscriber of the pointer
4. The current endpoint is the owner of the pointer

Are there any more constraints we need to add? Can we remove some?

I am not so sure if we need 4). If the receiver endpoint trusts the sender, it can also intialize a foreign pointer with a preemptive values provided by the sender (which is not the owner of the pointer).
Currently, with 4), we loose the ability to preemptively load pointers e.g. when the backend endpoint of a UIX app changes, but the pointers still have the previous backend endpoint as an origin (yes, this is an edge case, because normally you should never change the endpoint on the backend)