3365925 - FAQ: SACF_COMPARE after SPS and/or release upgrade (ECC/S4)

During an upgrade of a system, after SUM upgrade-post processing the following message is shown:

"Maintain Switchable Authorization Checks"

SUM-Phase: MAIN_POSTPROC/REQ_SACF_COMPARE

Maintaining switchable authorization checks is important for the security of your system landscape. 
Run transaction SACF_COMPARE to take over authorization scenarios that are relevant for your business processes.

Is this step to run SACF_COMPARE mandatory after SPS/release upgrade (ECC/S4)?

The following questions will be addressed in this document:
1. Is this step is mandatory to be executed after every SPS upgrade 
2. What exactly we should compare in SACF_COMPARE and how to identify what exactly needs to be changed ?
3. Is this needed to be executed across all landscape (DEV, TEST ,Quality, PROD)
4. What changes SACF_COMPARE makes in system , does this cause any issue?
5. What will happen if we miss to run SACF_COMPARE after upgrade?
6. Which team ideally should perform SACF_COMPARE (Security/BASIS/ABAP/Functional team)

ABAP Platform

SACF, SACF_COMPARE, scenarios , KBA , BC-SEC-AUT-SWF , Switchable Authorization Check Scenarios , Problem