This is ridiculous and fun. Kind of too much, though; the way the document is worded makes it sound like it will happen any or every time 6 or more people are near a stockpile of explosives. Maybe my imagination is just way off and I'm overestimating one or more factors, but that sounds to me like it'd be catastrophic for any military bases or munitions factory if people just start chucking explosives around, and I can't imagine all the resources it'd take to monitor practically any supply of explosives and cover it all up. It'd make more sense to me if it was limited in some way like only landmines, or only munitions factories, or if the event was just really rare in general.
I'm also a little confused by the phrase "last chance to safely opt-out" if there's no harm to them during the game; rather, it sounds like their last chance to safely opt-in.
I love the idea here and the log is very funny, but I feel like it'd need more strict conditions to reasonably exist in-universe (and not drive the Foundation totally nuts over secrecy and resources; landmine frisbee fads would be one heck of a "Lifted Veil" scenario)