What is the political incentive to do this ever?
But, I just looked it up again for this comment and that same rule says "No changes to social security" in reconciliation. It is specifically called out as forbidden to touch via reconciliation unlike almost every other program. So, maybe you are right, it will just be ignored because it doesn't seem possible to quietly change.
If this budget hits the PAYGO limits, which is basically guaranteed, that will trigger automatic cuts to Medicare, so they can backdoor cut the program without anybody voting for that.