  We use the Athens Model Independent Analysis Scheme (AMIAS) to examine the
validity of using the Fermi-Watson theorem in the multipole analyses of pion
photoproduction and electroproduction data. A standard practice in this field
is to fix the multipoles' phases from $\pi N$ scattering data, making use of
the Fermi - Watson theorem. However, these phases are known with limited
accuracy and the effect of this uncertainty on the obtained multipole
extraction has not been fully explored yet. Using AMIAS we constrain the phases
within their experimentally determined uncertainty. We first analyze sets of
pseudodata of increasing statistical precision and subsequently we apply the
methodology for a re-analysis of the Bates/Mainz electroproduction data. It is
found that the uncertainty induced by the $\pi N$ phases uncertainty to the
extracted solutions would be significant only in the analysis of data with much
higher precision than the current available experimental data.
