[Gentoo]

Out of interest could a training organisation really authorise 100 hours of solo flight for a student?

I can't see the training need, and if allowed it would suggest the organisation is allowing someone to fly 'as if' they had a licence, when they do not.

The insurance aspect would also be debatable. Because the insurance coverage for students is surely only for flights required as part of the training.

[kanga]

ISTR in '80s in US reading in one of the GA magazines the lengthy but light-hearted account of a DC-3 ferry flight from California to Hawaii, IFR but VMC. There were on board 2 Type Rated Instructors, and the daughter of one of them who had just started her PPL course, with some but not a lot of dual SEP time logged. From soon after takeoff to soon before landing (for both of which the 2 rated pilots were in the pilot seats), with occasional breaks (duly logged), she was in the RHS and the 'sole manipulator of the controls' (also duly logged), with one or other FI in LHS (who signed her logbook to that effect). The father (and author) remarked at the end of the article that 'those logbook entries may surprise the FAA Examiner when she presents it for her PPL.'

A note in a later issue of the same magazine not that long later (IIRC) reported that she had duly achieved her PPL, ME, CPL and IR, the DC-3 hours being accepted at each stage.

[cotterpot]

The insurance aspect would also be debatable. Because the insurance coverage for students is surely only for flights required as part of the training.

I think you are looking for problems where none exist.
When an insurance company takes on a risk it generally only wants to know what the aircraft is going to be used for. And that can be very wide ranging.

During my PPL I spent many times ferrying aircraft on the ground to refuel/relocate/put back in hangar etc. all not part of 'training' as such. But useful none the less.