When your wireless device is not connected to a Wi-Fi network, it broadcasts a signal to scan for Wi-Fi networks in the nearby vicinity, which includes your device's unique physical hardware address (MAC).

Certain locations like malls, stores, or other public areas can utilize this MAC address to track your movements within their area. To prevent such tracking, you can enable random hardware addresses on your Wi-Fi hardware, making it difficult for these establishments to track your device as it scans and connects to Wi-Fi networks.