  Pauli spin blockade (PSB) has long been an important tool for spin read-out
in double quantum dot (DQD) systems with interdot tunneling $t$. In this paper
we show that the blockade is lifted if the two dots experience distinct
effective magnetic fields caused by site-dependent g-tensors $g_L$ and $g_R$
for the left and right dot, and that this effect can be more pronounced than
the leakage current due to the spin-orbit interaction (SOI) via spin-flip
tunneling and the hyperfine interaction (HFI) of the electron spin with the
host nuclear spins. Using analytical results obtained in special parameter
regimes, we show that information about both the out-of-plane and in-plane
g-factors of the dots can be inferred from characteristic features of the
magneto-transport curve. For a symmetric DQD, we predict a pronounced maximum
in the leakage current at the characteristic out-of-plane magnetic field $B^* =
t/ \mu_B \sqrt{g_z^L g_z^R}$ which we term the g-tensor resonance of the
system. Moreover, we extend the results to contain the effects of strong SOI
and argue that in this more general case the leakage current carries
information about the g-tensor components and SOI of the system.
