Does the Client have to be on-line, their devices and PC are in the Watched list?
I'll perform the Client Match unsupport commands and see what whappens, may be next week before I get results though...
I tried a few variations of the command on the master controller to gather trail-info:
(Aruba01) #show ap client trail-info 08:60:6E:AA:55:A1
Unknown Client:08:60:6e:aa:55:a1
(Aruba01) #show ap client trail-info 08 60 6E AA 55 A1
^
% Invalid input detected at '^' marker.
(Aruba01) #show ap client trail-info 08606EAA55A1
^
% Invalid input detected at '^' marker.
(Aruba01) #show ap client trail-info <08606EAA55A1>
^
% Invalid input detected at '^' marker.