For me, that was the whole point of having them. Low resistance, low current consumption. And you don't need to undo any screws to disengage worm gears, because the thing will backdrive all day long.
If you're going to be doing a bit of messin' with it, see if you can introduce different spurs to vary the overall ratio.
I'm going to be experimenting by replacing the Escap motor with one by Maxon, which is supposed to be even stronger, using the same bevel gearbox.
Meanwhile I've started to draw out the chassis spacers for 21mm gauge on nickel-silver sheet......