"So, are we being overly selfish when we want to maintain some of the risk in a wilderness canoe trip?"

selfish ?  maybe, but anything we want for ourselves is being selfish, so who cares.  My view, if you are electronically tethered to civilization, you ain't in the wilderness buddy.  Its either/or, not both  - if you can't hack being in "the wilderness", then don't go. Haul your security blaket with you and eliminate teh wilderness from your canoe trips - whichever 

Further, should the parks maybe start requiring the use of phones or SPOTs?

Absolutely not!  Maybe "they" should implant gps tracking chips is everybody - lots of good reasons to do that - makes catching criminals easy,  you can find out where you are if lost, etc.  Hell, lets bolt GoPro camers to everybody's forehead while were at it, so you can't lie about stopping at that stop sign when you caused a car crash.   Lots of this is almost already here, what with all the tracking they already do with cell pbones, and secrurity cameras and intersection camers all over the place.  Homeland security can look at your computer anytime thye want to to see what nonsense your up to - Big Brother IS WATCHING