  We report on a survey for strong (rest equivalent width W_r >= 1A),
intervening MgII systems along the sightlines to long-duration gamma-ray bursts
(GRBs). The GRB spectra which comprise the survey have a heterogeneous mix of
resolution and wavelength coverage, but we implement a strict, uniform set of
search criteria to derive a well-defined statistical sample. We identify 15
strong MgII absorbers along 14 GRB sightlines (nearly every sightline exhibits
at least one absorber) with spectra covering a total pathlength Delta z = 15.5
at a mean redshift <z> = 1.1. In contrast, the predicted incidence of such
absorber systems along the same path length to quasar sightlines is only 3.8.
The roughly four times higher incidence along GRB sightlines is inconsistent
with a statistical fluctuation at greater than 99.9% c.l. Several effects could
explain the result: (i) dust within the MgII absorbers obscures faint quasars
giving a lower observed incidence along quasar sightlines; (ii) the gas is
intrinsic to the GRB event; (iii) the GRB are gravitationally lensed by these
absorbers. We present strong arguments against the first two effects and also
consider lensing to be an unlikely explanation. The results suggest that at
least one of our fundamental beliefs on absorption line research is flawed.
