While overtaking a cyclist in conditions of limited visibility, outside a built-up area, should you use short horn signals?

Why?

The image shows fog that makes the cyclist and the road harder to see. When overtaking in fog outside a built-up area, a car driver must give short horn signals. These warn others of the vehicle's presence but do not replace checking that the manoeuvre is safe.

art. 30 ust. 1 pkt 1 lit. b Prawa o ruchu drogowym