  The focus on privacy-related measures regarding wireless networks grew in
last couple of years. This is especially important with technologies like Wi-Fi
or Bluetooth, which are all around us and our smartphones use them not just for
connection to the internet or other devices, but for localization purposes as
well. In this paper, we analyze and evaluate probe request frames of 802.11
wireless protocol captured during the 11th international conference on Indoor
Positioning and Indoor Navigation (IPIN) 2021. We explore the temporal
occupancy of the conference space during four days of the conference as well as
non-cooperatively track the presence of devices in the proximity of the session
rooms using 802.11 management frames, with and without using MAC address
randomization. We carried out this analysis without trying to identify/reveal
the identity of the users or in any way reverse the MAC address randomization.
As a result of the analysis, we detected that there are still many devices not
adopting MAC randomization, because either it is not implemented, or users
disabled it. In addition, many devices can be easily tracked despite employing
MAC randomization.
