If its a wifi signal...I think that's a different frequency range than used for remote control devices such as drones?
Also, most game cameras are passive, in that they have a motion detector (IR for example) that starts/stops recording as something moves in its detection path.
The user than goes and downloads the data, and resets it, etc.
If its using wifi, that has a limited range, so, a game camera using wifi would need a transmitter to then uplink the collected data or live images, etc...to reach someone not on the property, perhaps a cell phone type link, etc. (Telemetry equipment, etc).
To detect THAT, you'd need to be able to detect cell phone related frequencies...and, you'd need to do it during a transmission (No detection of a receiver, only of a transmitter).
IE: Wifi is not a long enough range game cam technique unless the user is already onsite.
There ARE cell phone frequency type game cameras that can test, email, etc, when game is found...but the Wifi versions are meant for the hunter to be able to download the data via wifi, instead of unmounting the camera to get the SD card out, etc. (They are not transmitting otherwise).
I don't know of any game cameras that use wifi other than that use...as even 100' is a long range for wifi...and a few hundred feet would be the limit w/o a directional transmission dish, etc.