Last Call Review of draft-ietf-netconf-restconf-notif-13

Request Review of draft-ietf-netconf-restconf-notif
Requested rev. no specific revision (document currently at 13)
Type Last Call Review
Team Security Area Directorate (secdir)
Deadline 2019-04-12
Requested 2019-03-22
Draft last updated 2019-04-11
Completed reviews Yangdoctors Last Call review of -12 by Robert Wilton (diff)
Secdir Last Call review of -13 by Aanchal Malhotra
Tsvart Last Call review of -13 by Wesley Eddy
Genart Last Call review of -13 by Robert Sparks
Opsdir Last Call review of -13 by Dan Romascanu



The document is very clear and concise.  I just have one minor clarification question.
Section 3.4 Page 9 that says the following:
"In addition to any required ........SHOULD only be allowed......".  

Is there a reason for using SHOULD instead of MUST?