Pawelcn,
The regulation states:
1910.178(n)(4)
The driver shall be required to slow down and sound the horn at cross aisles and other locations where vision is obstructed. If the load being carried obstructs forward view, the driver shall be required to travel with the load trailing.
Conceivably, you could make the argument that the horn does not need to used at intersections where vision is not obstructed. In my opinion, sound the horn. Yes, it is annoying to the people in the area but it lets them know the forklift is there.
MikeCJ