Currently on the defaults for IO this answer is does not have enough positive votes to be instated. At press time it has +11-6 +18-9, defaults are required to have:
5 net votes and at least twice as many upvotes as downvotes.
However only a day ago this method was valid (If memory serves it was +10-2). In fact it has changed at twice today as far as I can tell. And since this question has been asked it has continued to fluctuate between valid and invalid. This has the strange consequence of making it a default for some questions but not others, depending on the time they were posted.
This would be bad enough but to make matters worse we can't know when it was a default and when it was not because voting records are not kept, or at least are not accessible. We can only make guesses or try to remember. And users with insufficient reputation can't even look at the votes to tell if it is a consensus.
What should we do about answers that are bordering between valid and invalid causing them to fluctuate between allowed and disallowed by default?