People who think Google is never wrong blithely follow Google Maps’ directions to my apartment, and are never heard from again. Our best guess is that they got into the wrong lane on Mass Ave, realized that they could not, in fact, turn left down some street that Google thought they could, and are still looking for a place to bang a U turn.
(Oh, they never returned, no, they never returned, and their fate is still unknown….)
I’m not sure this answers the question, but it does weaken Google’s reliability.