I recently ran across some WIFI adapters on Amazon that claim to have 2000mW of power. However, to the best of my research, there is an FCC limit of 1000mW on omnidirectional antennas. Are these devices only for use outside the USA?
Edit: I understand most people here are not lawyers so I probably shouldn't have asked for exact legal advice. Rnxrx has however provided some very useful information regarding how wifi signals are measured which should be useful outside of legal and locality spaces. I suppose the question would be better geared towards how the power advertised by a manufacturer can differ from the radio transmitter's actual power.