Some skeptics claim that an simplistic experiment should be done in parapsychology to demonstrate psi instead of an complicated one. The problem is that was already done with ESP cards they produced persuasive evidence for ESP, but the results were ignored.
Random number generators have many advantages over earlier research such as using tossed coins or dice. In the RNG experiment, great flexibility is combined with careful scientific control and a high rate of data acquisition.
Here is an good link refuted common criticism thrown at parapsychological experiments. It also discusses the hundreds of experiments that support psi, and also gives detail information on the experiments being repeated.