RFC 2119 agrees [1] as does US law [2] with exception of Illinois apparently. Seems to be ill defined and not preferred in the UK, sometimes deemed inappropria

RFC 2119 agrees [1] as does US law [2] with exception of Illinois apparently. Seems to be ill defined and not preferred in the UK, sometimes deemed inappropriate [3]. Perhaps the UK will interpret as per RFC-6919 [4] instead. 1. MUST This word, or the terms "REQUIRED" or "SHALL", mean that the definition is an absolute requirement of the specification. [1] - https://www.rfc-editor.org/rfc/rfc2119 https://www.rfc-editor.org/rfc/rfc2119 [2] - https://www.law.cornell.edu/wex/shall https://www.law.cornell.edu/wex/shall [3] - https://www.law-office.co.uk/art_shall-1.htm https://www.law-office.co.uk/art_shall-1.htm [4] - https://www.rfc-editor.org/rfc/rfc6919 https://www.rfc-editor.org/rfc/rfc6919