Does a Wireless-B device slow down a Wireless-G network?

The wattvision gateway, pictured below, is an 802.11B device.  It connects to your home's network and uploads the energy use data it gathers from the wattvision sensor attached to your meter.

Some of our customers have qualms about the speed of our gateway.  Won't a wireless-B device on my G or N wireless network slow down traffic for everyone? The short answer: no, it won't.

This paper, published by Microchip last year, is a study of network performance in a mixed networks and reaches this conclusion.  Can you cite a study that proves otherwise? Let us know!