Except if you are going for obviousness you want to start with people who haven't seen the patented material. You put them in the metaphorical clean room and t

Except if you are going for obviousness you want to start with people who haven't seen the patented material. You put them in the metaphorical clean room and then argue the patent invalid because some rando people came up with the same solution to the problem. And for prior art you need a group of "clean" people who were using the process/device prior to the patent, which is especially useful when dealing with trade secret material that, fearing a leak, a competitor is trying to patent. You need people clean of any taint from that competitor.