Switch on the lights better than not switching on the lights.
Not a fool proof plan but at least a slight deterrent.
A theif operate better in the darkness, you just lessen their advantage.

I will close the sheer but not the curtains.
Sheer is good enough for privacy when the inner house light is off, you can still see outside (with the outside lights on), but outside can't see in.
If curtain close, anything happen and you suddendly switch on inside light, nobody outside can see in thus even if neighbour is friendly and helpful, he dunno if there is an emergency happening or not.