Share 'Do discs fly more or less stable at increased altitude?'

I've heard many competing theories and opinions about how discs fly differently at altitude.  Many say discs tend to fly more overstable in thinner air (higher altitude) as compared to sea-level, while some others have said the opposite.  While this kind of competing (mis)information is common throughout our society, it does us little good when making informed decisions.  We need some way of sort…