  A certain class of parametric down-conversion Bell type experiments has the
following features. In the idealized perfect situation it is in only 50% of
cases that each observer receives a photon; in the other 50% of cases one
observer receives both photons of a pair while the other observer receives
none. The standard approach is to discard the events of the second type. Only
the remaining ones are used as the data input to some Bell inequalities. This
raises justified doubts whether such experiments could be ever genuine tests of
local realism. We propose to take into account these "unfavorable" cases and to
analyze the entire pattern of polarization and localization correlations. This
departure from the standard reasoning enables one to show that indeed the
experiments are true test of local realism.
