The use of random MAC addresses is considered as an important tool to improve a user's privacy on a Wi-Fi network.Although this technique was proposed since 2014, its implementation was not effective immediately but had an uneven evolution over the following years.This paper studies the evolution of random MAC addresses based on the analysis of data collected in public Wi-Fi networks located in different areas of Latin American countries from 2016 to 2021.Statistical analysis is performed using the analysis of variance technique (ANOVA) that tests whether there are significant differences in the rate of MAC randomization over different periods of time and thereby identified an uneven evolution of the implementation of MAC address randomization measures in mobile devices with different operating systems, and also the massification of these measures from 2019.The development of the massification of randomized MAC addresses and the impact of the existence of centralized and widely controlled operating systems, such as iOS, is evident.