I have rented a spot messenger every year for the last about 5 years. I have always had good results on getting my messages and tracking locations through.  Maybe that is because I read the instructions and ware it on the top of my shoulder where it has a clear view of the sky rather than under my belly on my belt.  I assign a person to be my spot watcher.  That person knows what the buttons mean.  My spot watchers have called my outfitter and told them I would like to be picked up a day early at Hook Island because I pushed the button we had agreed on for that purpose.  I have always arranged to have a signal that means I am ok but I need help getting out of the park. If I send that message I will be expecting help within a few days at my present location. The old Spots have 2 buttons that will send non-emergency messages.  They can be used as one’s and zero’s only you can only send 1 per hour so make your messages short.