Using a gpx that someone has been created for the exclusive use of paying participants wouldn't be illegal. There are no laws against it. But it would be considered immoral.
Sorry. I don't think following a route described by a gpx file is immoral, whoever has created the file. It's a route description; no more, no less; and as has been said, the roads are free to ride, without the handicap of moral conflict.
I'm pleased to see all and every cyclist out on the roads. Confess I was not so pleased to see some LEL riders joined by a strong rider from St Ives who shamelessly (well the blokes showed no shame) offered her wheel to all and sundry (so I rode away from them
and got lost in Cambridge). On the plus side it would have been nice for the well built dad to have support and the riding companionship of his daughter (assumed
) on that last day after the 'winds'.
"9.9.3 Participants may ride singly or in groups and may pace each other but may not be paced by
any other cyclist [ie non-participant] or motor vehicle."
If I wish to use a loo in a pub or even a McDonalds (without being a customer), I will always ask permission. To use it without permission is impolite (but not immoral imo).