Comment by tialaramex

Matt Kulukundis (sp?) mentions this problem is his talk about Google's rather fancier Swiss tables.

At that point their debug builds would do a "coin toss" with 50.3% chance to be heads during hash table insertion and he expected some idiots would use that to generate random bits then be annoyed if it breaks. I believe in production it's entirely seeded from ASLR, so you're actually leaking address layout info if you try to use these bits as entropy instead of just to make the hash table defeat your bad unit tests.