The problem I have with this, and I seem to be alone on this, is that
1. You are not confirming the 3 DNA testers, you are confirming a series of parent/child relationships.
2. A single triangulation does not confirm the relationship between 3 DNA testers.
I noticed a significant change to the help which now excludes confirming with DNA any shared ancestors.
"The parent/child relationships in an ancestral line from each tester in the TG back to (but not including) the shared ancestral couple should be marked as "confirmed with DNA"."
Technically, you can "confirm with DNA" up to but not including the shared ancestral couple given the guideline...
"You will need at least three test matches (you and two or more distant cousins) who all match on the same segment of DNA to confidently confirm which ancestor(s) you have in common."
This is because Phillip and Katina are two of your distant cousins but since they are siblings, they only match 1 distant cousin. If they could match to your sibling as well, the guidelines are followed.