I hear many people say on this forum from time to time that the Predator patent is invalid becasue their patent describes a "hole" or "air", etc. That is completely obsurd. The patent is on a DESIGN that includes a large hollow area, among other things. By all means you can patent that, and they did. The only thing that would invalidate the patent is if someone else did it before them, and their was proof of it. This proof is known as "prior art". I'm not going to debate that aspect of it, as I have no idea if others were doing that before Predator. But I do know that that the techincal issues in the patent are sound.
I'm by no means a patent expert. I'm an engineer for a consumer products company. We frequently have to design around competitor's patents. We also go after competitors when they infringe on our patents. It IS both funny and frustrating when some simple and obvious things get patented, but that's the way it is. In the end, only the lawyers make money.
My experience with patents is that unless the company that infringes upon our patents is a MAJOR competitor, we don't go after them. The court and lawyer costs are not worth the small amount of money we would get from them if we won. If you do go after someone and win, the winninng party would generally get a percentage of the offending party's total sales of the infringing product. What percentage is decided in court.
That said, I think if a custom cuemaker knocked off ANY patent, it would not be worth going after them. The hassle and legal costs in my opinoion would not be worth it if the custom guy makes only a few cues per year. Only if a major manufacturer knocked off someone's patent would it be worth going after them in my opinion.