HI,
I was just watching this Video of Mike Cohn:
https://www.mountaingoatsoftware.com/agile/scrum/meetings/sprint-planning-meeting
In Minute 1:05 he states:
"Most of the high priority items should be aligned with achieving the sprint goal. But it's quite often the case that some high priority items are unrelated to the goal and that's ok."
However, he never mentions what happens in this case: