I had no idea Waze was powered by anon crowd sourced map editors. If anybody here is doing it, what's the motivation? Personally I'd never disclose my shortcuts or free parking spots.
(And while that's an exaggeration, Waze has consistently been far more likely to send me down unpaved roads, ridiculously steep hills, and, yes, unprotected left turns onto busy highways, presumably because the residential road I was on was lower traffic than the parallel road one block away with traffic lights.)