Surely saying 'Cleared ILS approach' means use both the localizer and the glidepath? That's what the ILS chart depicts. Clearing someone for the localizer approach only would allow them do duck down to the intermediate levels as depicted on the approach chart.
I, too, have never seen someone dropping below the glidepath when cleared for an ILS either, but I'm not doubting the events happen. Would an education program be better than catering to the lowest common denominator? Why is the UK the only place I know of that uses this R/T because of this problem?
Cheers,
NFR.