It would take someone more skilled than I, or with better tools, to check current in a fuse box without removing fuses. Maybe I should watch that guy and get better...
You can check continuity across the contact points, but measuring a 75mA current via the voltage drop across a 0.0034ohm resistance (give or take) means reading 0.2mV, which is… borderline for a consumer multimeter.
I wonder if one couldn't identify the time it takes for the battery to get to some low point (50%?) and then determine the order of magnitude draw they would be looking for. 75mA would take a long time (I think) to drain the battery to where starter can't turn over (like a week?).