Pretty sure everything would be passable, since everything is a html entity, a large combination wouldn't really be complicated, just a bit tedious. Relevant link.
Granted, I guess if you went really large it'd be so tedious that someone would just write a bot to parse it for them or something.
A password built into the storygame, or a link hidden on a pixel (I think i heard you could do this) might work as well, but I guess if I'm going to pull the good ol' bot card, nothing will really stop someone who knows what they're doing.
So I'd say, maybe have it be the classic: 'This is the first page in your adventure game. To change this text or edit the page further, switch the page view by clicking on the edit button above.' Then hide a link somewhere, since no one would expect it. Thus you'd more so be relying on deception than outright wall making.