COTS loggers - Plan B

Finbar wrote:
...
Unless I want to submit for a badge. Then, it's far too late to
download the flights when I get home - no, I have to download them on
the field in front of an Official Observer. To do that, I have to buy
a laptop, because if I download the files at home I might cheat.

No, you can't. This is the miracle of the digital signature. It
ensures that only this logger can produce this file, independently
of the way it was downloaded. Of course you can cheat by downloading
another logger, so it remains to the OO to check that your logger,
identified by its serial number, was in the glider during the flight,
which has its begin and end time in the IGC file, as well as the
serial number.