Implications of Logical Order Exception Property

[Richard Wordingham]

What is the significance of logical_order_exception being true for a
character?

TUS 9.0 Section 4.3 appears to claim that such characters need to be
rearranged 'logically' for searching and sorting.

However, I cannot see how they need to be rearranged for searching.

Is this property a general warning, or does it mean that swapping with
the *next* character gives a less bad sorting experience?  For example,
why doesn't U+17CC KHMER SIGN ROBAT have the property?  Consonant +
ROBAT has to be rearranged to ROBAT + consonant for sorting - ROBAT is
a repha stored after rather than before the *visual* base consonant.

Richard.