Brushes are very effective for dissipating static charge in many applications, however, they (or the other object) must be grounded.
Sharp points on conductive objects in an electrostatic field, cause the electric field to become very concentrated at the point. This causes a corona discharge at the point where the air becomes ionized. These ions in the air move toward the opposite charge and get neutralized. But there has to be a source of electrons. The earth is considered to be an infinite source or sink of electrons. A finite object will quickly become charged as it is sourcing or sinking electrons.
Normally the brush is grounded and will dissipate charge from nearby objects without an arc discharge. This is how some static eliminators work, and some argue that is how lighting rods work. However, lighting will also just strike the nearest ground. I guess the argument can be made that a boat or other object that is charged at same polarity as the lightning will tend to repel the lighting. There are so many other factors involved with where lightning will strike that it is difficult to statisticly prove that this hypothesis actually works.
