I, like Wendy, have yet to bite the bullet and invest in a Spot Tracker, but definately close to getting one.
I would be using one for motorcycling, bush walking, skiing and 4wd driving. Obviously when walking or skiing I would be wearing the device. I have seen a number of bikes using the Ram mounting system but as BrookeSTer and WAG have pointed out, if things go pearshaped, having the Spot on you would be the way to go. . . . Thanks for that valuable advice guys . .