  We report on a series of Swift/XRT observations, performed between February
and 22 March 2012, during the quiescent state of the neutron-star X-ray binary
SAX J1750.8-2900. In these observations, the source was either just detected or
undetected, depending on the exposure length (which ranged from ~0.3 to ~3.8
ks). The upper limits for the non-detections were consistent with the detected
luminosities (when fitting a thermal model to the spectrum) of ~1E34 erg/s
(0.5-10 keV). This level is consistent with what has been measured previously
for this source in quiescence. However, on March 17 the source was found to
have an order of magnitude larger count rate. When fitting the flare spectrum
with an absorbed power-law model, we obtained a flare luminosity of (3-4) 1E34
erg/s (0.5-10 keV). Follow-up Swift observations showed that this flare lasted
<16 days. This event was very likely due to a brief episode of low-level
accretion onto the neutron star and provides further evidence that the
quiescent state of neutron-star X-ray transients might not be as quiet as is
generally assumed. The detection of this low-level accretion flare raises the
question whether the quiescent emission of the source (outside the flare) could
also be due to residual accretion, albeit continuous instead of episodic.
However, we provide arguments which would suggest that the lowest intensity
level might instead represent the cooling of the accretion-heated neutron star.
