Ok, so here is the story of how it most likely (IMHO) happened. Keep in mind, these are not confirmed facts. I cannot provide a link to the blog I received this information from. If you google "Max Headroom" and "Indiana University", the first result is the blog where I picked up this info.
(Mind you, I attended IU myself and was actually in the same program years later as some of the POIs which is why I follow this detailed account, and believe it could definitely be the true story. FWIW, though I don't know any of these people personally.)
The story itself is pretty strange, and unfortunately there seems to be a tragic end to this. Apparently, the individual this blogger received this info from knew the POIs very well, but he told the story to this blogger on the condition he remain annonymous.
So apparently this all begins with the punk music scene in Bloomington, IN in the '80s as well as IUSTV, the student-run television station at the University.
(Just a bit of background info, I attended IU from '99-'02. IUSTV apparently didn't come into existence until '02 or '03, so this part confuses me a bit, as it wasn't around when I attended. We had WTIU, which was the PBS station in Bloomington, and I actually did some volunteer production work for them, and was in a student-produced variety show that aired several times. In this account, I am not sure if the blogger or teller of the account is confusing IUSTV with WTIU, but perhaps there was a fully student run channel called IUSTV back in the 80s and it just got taken out by the '90s, and then was brought back to life in '02? Not sure about this, and I'd have to do more research. I'll just stick with IUSTV for now, but it could actually be WTIU).
Anyhow...this blogger came into contact with someone on a tv broadcasting info forum. Apparently this guy knew who was responsible. Back in the 80s in Bloomington, there was a punk band called The Blood Farmers. The lead vocalist was named Eric Fournier, and he was very familiar with video editing, and this particular person the blogger met wanted to make a music video back then.
They all became friends and hung out, and made music videos together. It seemed they wanted a larger audience to see one of their music videos, and one night someone had the bright idea of trying to gain access to a TV station's signal and show their video. A few of these students they were friends with were getting degrees in mass communications, and had access to borrow broadcasting equipment from IUSTV (again, not sure if it was called IUSTV back then). A friend and his band had a touring van, and they made the four hour drive to Chicago with the broadcasting equipment. They chose Chicago because it was the largest station around within driving distance.
However, they soon realized if they showed a music video, they would obviously be caught, as it would be more than apparent who signal hijackers were. Now it turned into doing something hilarious just to prove they could do this. So Eric (who was a rather flamboyant character with a lot of charisma) had the idea to dress up as Max Headroom, and according to the source, he was the one in costume. They improvised the entire scene in a band's practice area. They scored by breaking into the signal from PBS, as a public station's transmission wouldn't be as secure....and the rest is history.
Apparently investigators of the incident did look into IUSTV staff, and even Eric himself; the investigators were indeed able to gather information that they did borrow the broadcasting equipment and took it to Chicago to practice, and did use a ton of power during the times the hijacking occurred, but Eric and his friends all claimed that they had been making a music video. The investigtors left them alone shortly after.
Eric Fournier was indeed the lead vocalist of The Blood Farmers. The blogger checked out the other names he was given and they were all on staff at IUSTV.
If anyone is interested in internet memes, you may have heard of a bizarre character named Shaye Saint John. This character was/is a creation of Eric's. Really bizarre stuff, but they say the style and editing of these videos, and even some of the movement matches what is seen above in the MH video.
According to the source, Eric has never been one to downplay his role in all this.
The most tragic part of this is that Eric Fournier passed away in February 2010...so statue of limitations or not, it's a moot point.
No concrete evidence or proof, but it seems pretty believable to me...