Message

Location identifiers SHOULD be GLN or GSRN

Context
cac:Delivery/cac:DeliveryLocation/cbc:ID[@schemeID]
Test
some $v in tokenize('GLN GSRN', '\s') satisfies $v = @schemeID
Usage
/ ubl:CreditNote / cac:Delivery / cac:DeliveryLocation / cbc:ID
/ ubl:CreditNote / cac:CreditNoteLine / cac:Delivery / cac:DeliveryLocation / cbc:ID