This is exactly what I've seen happen in my experience and have often wondered about alternatives. Bridgewater, for example, uses a system that allows for feedback from anybody at any time [0], but I suspect that presents new issues like negative reviews from rival employees. Additionally, a lack of context could result in negative feedback for decisions that actually help the business (e.g. passing on requests to help colleagues with relatively low-value items in favor of focusing on higher priorities).

[0] http://www.businessinsider.com/bridgewater-employees-rate-pe...