  We present transport and scanning SQUID measurements on InAs/GaSb double
quantum wells, a system predicted to be a two-dimensional topological
insulator. Top and back gates allow independent control of density and band
offset, allowing tuning from the trivial to the topological regime. In the
trivial regime, bulk conductivity is quenched but transport persists along the
edges, superficially resembling the predicted helical edge-channels in the
topological regime. We characterize edge conduction in the trivial regime in a
wide variety of sample geometries and measurement configurations, as a function
of temperature, magnetic field, and edge length. Despite similarities to
studies claiming measurements of helical edge channels, our characterization
points to a non-topological origin for these observations.
