Here's the only "shall" I think you'll find in 265 IRT ankle boots:
CH 5, Annex C Service Dress No. 3
5.
Skirts and pumps shall not be worn on parade. For Army members, boots ankle shall be the normal footwear ordered worn on parade.
Canadian Armed Forces Dress Instructions
www.canada.ca
Almost every parade instruction/Admin O I've seen over XX years has said "
officers shall wear oxfords, NCMs shall wear ankle boots". Recently I was part of a mil funeral @ the NMC. As there was no instructions otherwise, I wore short sleeve shirt and oxfords and some people thought that was odd. Just tells me most people just aren't aware of para 5(b)(2) at link below.
Long-sleeved shirts:
- shall be worn by Navy members, and
- may be ordered worn by Army and Air Force members.
Canadian Armed Forces Dress Instructions
www.canada.ca
OldSolduer mentioned "the CO can order" aspect...265, Ch 1, para 8:
8. Control is exercised by local commanders who may standardize the dress of subordinates on any occasion, including the wear of accoutrements and alternative or optional items, subject to overall command direction.
** just to mention, there are other dress instr's to read/consider. I'm a 1 Cdn Air Div type, so operational dress is governed by a CADO, and then I have my Wing Dress Instr's to know/consider as well.