I like this idea.
But to avoid the Blair witch panic stuff I would just leave it open and the time limit to two minutes. Just a "If this tape is ever found" thing. So it could run a whole gambit... someone preparing a backup tape in case somethiogn ahpoens to them, or a personal prediction, or a will in a desperate situation... or a last message to someone else meant for hope rather than panic, etc.
Anyone who goes for the desperate panic will be flogged by the critics so i would hope people would use their imaginations.
I would approach it personally with a "if anyone ever views this tape, i'll be in a whole lotta shit" approach. Maybe disclose some personal secrets that you plan on erasing later.
Or maybe, if anyone ever views this tape, my paprachuting attempt didn't work," and maybe its not a plea but some last words left in case something bad could happen, but necessarily.
maybe they prepared the tape thinking the worst, and it didn't happen and then someone discovers the tape when it wasn't necessary and it effects the person. Not necassirly is the movie the actual tape, but the story surrounding the tape. there's a whole gambit you could go with this other than the last words panic thing.
I believe Stephen king used this concept for a short story, as well as some other writers. Its a great idea for a filmfight.
i like the idea alot.
It's better to try and screw it up then never try at all.
I'm not a film fighter, I'm a film lover.