In this paper we report the impact of the Random Waypoint model on infrastructure wireless networks that utilise multi-rate scheme. The Waypoint model causes a higher concentration of nodes near the centre of the mobility area. As a consequence of this, we show that a wireless network could appear to achieve higher capacity, and that base stations near the centre of the mobility area will experience higher frequencies of transmission rate change. These aberrations could affect simulation results that should be interpreted with care. 1.