Pizza itself might be a bit of a joke but looking for non-operational behavioral changes is absolutely real. The Cuban missile crisis was started in part because soviets played soccer and Cubans played baseball and the presence of soccer fields helped confirm soviet presence (in enough numbers to bother making rec centers). A more advanced version might be the public Strava data leaking US base layouts and locations or Strava helping the Ukrainians kill a Russian submarine commander.

Edit to add: you could also just figure out where your target orders pizza from and pay one of the dudes working there to tell you when there’s a spike in deliveries to your target.