It's not just older folks who think we're crazy for canoeing in the wilderness, especially solo.  Here in Ohio, I'm amazed how many people of varying age have similar questions and reactions experienced in Spartan2's post.  Isn't it dangerous?  What if something happens?  Aren't you afraid of dangerous or poisonous insects or animals?  What about bad storms?

As for SPOT, I've used one for several trips now.  The only issue that came up early on was the first time I couldn't get the thing to link to a satellite at a secluded campsite.  Usually my wife gets an email each night.  She said she was really worried when the email didn't come until an email came the following night.  We talked some when I returned home.  Since that one time, she now knows a day or two break in the daily emails is probably nothing....but a little worry is still there in the back of her mind.