  We address the problem of detecting bipartite Bell nonlocality whenever the
only experimental information are the intensities produced in each run of the
experiment by an unknown number of particles. We point out that this scenario
naturally occurs in Bell experiments with parametric down-conversion when the
crystal is pumped by strong pulses, in Bell tests with distant sources and in
which particles suffer different delays during their flight, in Bell
experiments using living cells as photo detectors, and in Bell experiments
where the pairing information is physically removed. We show that, although
Bell nonlocality decreases as the number of particles increases, if the parties
can distinguish arbitrarily small differences of intensities and the visibility
is larger than $0.98$, then Bell nonlocality can still be experimentally
detected with fluxes of up to $15$ particles. We show that this prediction can
be tested with current equipment in a Bell experiment where pairing information
is physically removed, but requires the assumption of fair sampling.
