Single-player causes multiplayer glitches

I'm sure many people have seen the flying archer glitch, and the "walking through the spawn barrier" glitch. Had a guy cap the flag during spawn time just now. Anyway, when asked, these people always say they had been playing a single player mode just before, and recently a lot of new players have been abusing these glitches. One claimed that the "tutorial is broken for me" and also suffered from these superpowers. So I'm guessing that the tutorial mode in particular is a culprit that needs to be weeded out asap. I didn't put this in a proper bug report section because these are speculative observations, and let's face it, none of the new players will ever realize there's a forum, let alone file a bug report with detailed information. Is there any more information on this, since I'm sure I'm not the first person to post about it?