  Plasmonic antennas offer promising opportunities to control the emission of
quantum objects. As a consequence, the fluorescence enhancement factor is
widely used as a figure of merit for a practical antenna realization. However,
the fluorescence enhancement factor is not an intrinsic property of the
antenna. It critically depends on several parameters, some of which are often
disregarded. In this contribution, I explore the influence of the setup
collection efficiency, emitter's quantum yield and excitation intensity.
Improperly setting these parameters may significantly alter the enhancement
values, leading to potential misinterpretations. The discussion is illustrated
by an antenna example of a nanoaperture surrounded by plasmonic corrugations.
