The most obvious question would have to be the one relating to Phil's competence as a canoeist. As we know, he swamped the canoe by steering it into the wind like an idiot and he and John abandoned it to swim for shore like the panicky imbeciles they are. Did they not realize at all what the implications of an abandoned canoe were? Did it not occur to either of them that the general consensus was that the woman who actually knew where they intended to go and her friend might end up having to identify their remains?
Of course, that was not the most devastating little question that they'd be asked. What interests me is where they landed. As we saw, there was part of an old shack on that island that they'd made into a lean-to. A normal person of average intelligence and possessing something I like to call a survival instinct would come to the conclusion that this place is a campground of some sort. It hasn't seen active use in a while but, as I mentioned earlier, the men flying the rescue plane thought it quite likely that John and Phil were camping there. What this means is that there's an easy way to get to the mainland. There might even be signs of civilization like a marina on the shore that they might have seen had they had the rather obvious idea of walking around the island to see if there was a way of getting to dry land. John and Phil did no such thing. This means that the head of the rescue team would end up asking the two clods if they wanted to die of exposure fifty feet away from rescue.
This, I should think, is why it is that John spends most of this August hiding from the world because of some sort of vaguely defined humiliation. Simply put, someone made him admit that he doesn't belong in the wilds because he's too soft and stupid to endure anything more traumatic than light drizzle and having to admit being in the wrong is, as always, something too horrible to bear.