I never had any problems with others getting into my casting zone. At times I had people stand behind me while flycasting but thats a different issue.
I have not let seen a person cast a boat rod far enough to interfere with my line anyway. With a half decent technique and correct weight it is possible to get good distance but most seem to have strangely balanced tackle. I quite often use boat rods while surfcasting. With them you can,t be tempted to cast towards the horizon. They are no good when the sea is big.
All 3 times have been at the wairau bar when I was fishing just outside the mouth.Not all were boat rods and I prob only cut two of them off just an example of what happens to ya mono when it invades my space.
As you would know the bar can be very busy. I never surfcast there during the summer. I often watch people surf casting (while spinning) and have never seen them catch anything decent. A good red cod spot during the winter.