An analysis of recent free‐electron laser experiments in combined wiggler and strong axial magnetic fields shows that near resonance, &OHgr;∥=kwv∥, the proximity of the cyclotron maser instability precludes an unambiguous identification of the radiation mechanism (&OHgr;∥is the cyclotron frequency in the axial field,kwis the wiggler wavenumber, andv∥the axial electron velocity).