I used to love that show. I thoroughly enjoyed debunking their research and guessing which "researchers" were manufacturing fake evidence and which were hired as "straight men". For instance, in the first season of the series, I suspected Brian Harnois, the equipment manager, to be behind many of the "paranormal" incidents. I noticed that after he left temporarily, there were fewer such incidents, and those that did happen were less showy than the ones in previous episodes. When Brian Harnois returned to the show, the spectacular events kicked up again.
I've also always suspected Grant, since so many of the events seem to center around him. In one episode, while the camera was pointed directly at a table where Grant was sitting, the table seemed to "jump", and of course the team went wild. This scene was an obvious set-up from the gate. Grant called the cameraman over and made him focus the camera on the tabletop, claiming he needed the light from the camera in order to change the batteries in a piece of equipment. Not only does each cast member have a flashlight, Grant has enough experience working in the dark that he should have been able to change the batteries without any light at all. I've worked in a darkroom before, and I can load and unload a camera, change batteries, change reels on negatives, flip the film, load it into any type of carrier you want, and pour myself a glass of water without spilling it in pitch-darkness, and I don't have near the "years of experience" that Grant Wilson claims. Grant distracted the cameraman, and when his camera was directed away from the rest of the room, he kneed the heck out of that table, making it "jump".
There are a few other incidents focusing on Grant Wilson, such as the collar pull. There was one when a faucet "turned itself on" in another room. Jason Hawes and Grant Wilson, using their elite Roto-Rooter skills, swore it was the type of faucet that could not engage itself due to a buildup in water pressure and gases. However, the camera was focused on Jason, who was standing on a ladder in an attic at the time the water went on, and Grant was supposed to be at the bottom of the ladder, near the bathroom where the faucet was. Of course we couldn't see past Jason to determine where Grant was when the water went on. We just had to take his word for it, naturally. There was another incident where a mysterious piece of glass materialized out of nowhere, and of course it didn't match the nearby broken windows. That's because Grant Wilson tossed it when the camera was turned away. You couldn't see him, but his shadow was visible in the shot.
Jason Hawes is aware of the fakery and helps plan it, but he does less of the actual work of faking "evidence". Early on in the first season, he established himself as the "tough boss" and was less likeable than Grant Wilson. A lot of the show depends on the likeability of the cast, as it adds to the overall credibility of the show. I believe that due to Grant Wilson's gentle, "nice guy" persona, he's the natural person to perform a majority of the hoaxes.
An interesting thing about the show is the cast turnover. There have been so many people who have been in an episode or two, never to be seen again. Some of the older cast members have disappeared or been transferred to Ghost Hunters International. A lot of these started out as low-level "investigators" on the main show. I believe that the franchise (Ghost Hunters + Ghost Hunters International) needs a constant influx of new cast members who aren't aware of the hoaxing in order for the shows to survive. For instance, members such as Dave Tango, Dustin Pari, and Andy Andrews were very gullible when they first started on the show. As they became more experienced and learned how to set up hoaxes themselves, they were moved to GHI and new novice investigators were brought in, so that there's always someone who's scared out of their wits when something "paranormal" happens. Remember Keith and Carl Johnson, the twin "demonologists"? It's my belief that they are rarely on the show because either one would blow the whistle if they saw any fakery whatsoever, especially considering that Keith is a former priest. You'll also note that in the few episodes where they appear, the "paranormal events" are of the less flamboyant variety, and never center around either of them. Even though I personally feel like demonology is a load of crap, there's no doubt in my mind that the Johnsons believe in it deeply, and are honest men who want to help those that are afflicted by "demons".
I believe that the reason that the show has such a high turnover rate is because some of the former straight men are true believers, and they are so offended when they discover the fakery that they simply quit the show. The participation of other members, like the Johnsons, is kept to a minimum if it seems like they would disclose the hoax if they saw it happening. Those that discover the hoax and willing to stay are taught to do their own hoaxing, promoted, and transferred to GHI.
It's possible that TAPS began as a genuine hunt for paranormal activities, and the Ghost Hunters show forced the members of TAPS to begin faking evidence. After all, who would still be watching, if they never "found" a single thing? As it is, they have a hardcore following: people who believe in ghosts, and skeptics who want to catch them faking. 95% of their "evidence" comes from misusing the equipment or simple mass hysteria; only 5% of it needs to be actively faked. That 5% is enough to keep both the believers and the skeptics on the edge of their seats.