When David gets the texts on Day 3 his phone says 7:19 AM but it says Today 6:43 PM on the message from Josh.
If campers put their heads at opposite ends of the tent like they do the first night, one of them will be lying downhill and have a terrible headache the next day.
The note says "than making techno music" not just "than making music" and "Yours forever and ever" not "Sincerely yours" and "intercourse activity" not "intimate relations" and a single word at the end, not "You just got punked" as the voiceover says.