I'm kinda surprised at how many rumors and conspiracy theories wound up being true over the years. From hearing that BA was gay way back when he was on Toy Machine, to pretty much everyone on Girl/ Choco being crack heads, to the whole DWay thing, all of that wound up coming to light as factual. It just goes to show that skateboarding is full of gossipy bitches who are unable to keep to themselves.
I would say that the one I always come back to is how Crailtap/ skateboard media tried to cover up Guy's crack cocaine addiction, and then just attributing it to general depression without cause once it came to light. I remember when skateboardrumors.com came around back in the early 2000's, I used to be really heavy on it for a long time. We wrote about everything we heard through the grapevine regardless of how fucked it was, and for some reason no one was talking about Guy's disappearance from skateboarding and why it happened. The only time I ever had any sort of backlash was when I posted about why Guy disappeared, and I told the story I had heard from my friends in Manhattan and BK about him becoming a crackhead after sleeping with Justin Pierce's fiance (Guy's current wife) and Justin subsequently hanging himself in his Vegas hotel room. Guy wasn't allowed to come back to NYC for quite sometime after all of that happened, as the skateboard community here wasn't all that welcoming after the fact for obvious reasons. Well, that thread became the biggest thing on that board at the time and was subsequently taken down w/ my account suspended. I found it weird due to the nature of the board, I mean we talked about everything from Ryan Fabry fucking Sheffey's wife to Danny Gonzalez being blackballed from the industry due to his Thrasher Skate and Destroy videogame lawsuit (where his kickflip melon at Wallenburg was swept under the rug) to DWay evading murder charges on behalf of Josh Swindell. So I did what plenty of people here do, and I made a new account with a similar name and re-made the post. I included everything from the original, with an update on what happend to my acct and asked publicly why I was ostracized. One of the mods popped up, and said that I was spreading false information and that they can't stake their reputation and bla bla bla "Guy doesn't even have a drug problem, you made that up." I was banned a second time from there, and the board pretty much became a police state for anyone who attempted to revive the topic. Skateboardrumors.com only lasted another few months to a year after that, but during the time it was still around I was able to find out that someone who worked at Crailtap actually knew the guys who modded the message board and demanded that the topic be censored, and that was why the thread was considered "taboo." Even today, there was no mention of why Guy spiraled out of control with his crack addiction in his Epicly Later'd; it's as if Guy was just someone who was having a normal bad day and picked up a crack pipe and that was that. And it wasn't anything malicious on my part, since Guy is (or at least was) one of my favorite skateboarders. Hell, I was riding a Guy Mariano Krooked guest board during the time I made that thread, and I still have another one in my room since I bought it thinking it'd be the last board I would be able to buy with his name on it. The only other time I faced any sort of repercussion on skateboardrumors.com was when I mentioned that cocaine was involved in Keenan Milton's death; my post was removed, but the ones that simply said "drinking" or "partying" were left up since it didn't cross the line in their eyes.
That's the only personal skateboarding "conspiracy" that I could come up with, the rest are just rumors (many of which I know to be true) about individual skateboarders that don't involve another individual planning for or against something in particular, and many of them have already been listed in this thread.