maybe a transmission could be heard by noone and be on a band were it couldn’t be heard by anyone, I suppose it could go into some equipment nearby cause undesired operation, I don’t know if 1w or 4w could do this on mw, its kind of an unknown, I suppose its just the rf field if its close enough.
Mw aerials tend to be long, from what I gather the most signal goes out from the middle of the wire, unless you had a huge garden it would be hard to get away from a road, its something thats in the air or going along a fence, the fence would hide it, but not the rf field.