I use the SPOT Gen 3 device to check in almost every night. A few nights this has failed. The device gives me no indication of this and after calling the company, they don't think my device is defective, but they don't know what the problem is. But about 3 failures out of about 69 days of hiking means a failure rate of about 4%. I can live with that. So don't worry if my GPS message doesn't get posted for the night.
(As to last night- I forgot. But I stayed at the Peter Grubb Hut. It was amazing)