My understanding - and only that - is that any necessary 'treatment' or gear required is on the starter's sheet.
If that is in fact correct, it is very likely that stipes forgot to notify the starter, or make sure the addition was noted.
Has happened to one of mine, starter was all set to carry the can, but when I rang him to discuss the 'blue' he confirmed that in fact the horse's requirements weren't added to his sheet. As it was the first time the horse had raced out of his district, the fault was pretty clear.
Horse hurt and scratched. No one offered to pay the acceptance fee, or the vet bill though...or the transport.