Opinions on safety of dropbox ???

[Mike O'Dell]

one of the primary exponents of teaching celestial navigation
(what you can do with a sextant) has the following observation:

      When crossing an ocean using only GPS,
      you don't know whether you're right
      until the LAST day.

Of course, redundant GNSS receivers are a good idea,
as are using the redundant GNSS constellations.
And if everyone gets their s??t scraped up in one pile,
using eLoran signals are a really good idea too since
they have vastly different failure modes.

     -mo