It's easy to see where a Note begins, because it starts with "NOTE" and some whitespace.
But it's often hard to see where it ends, because (as far as I can tell) the only visual difference between Note-text and normal body text is that Note-text is in a slightly smaller font (say, 10pt versus 11pt).
(And it's important to see where a Note ends, because that's a division between normative and non-normative text.)
So please do something to make the end of a Note more obvious. E.g.:
-- change the Note's typeface, text color (gray level), background color,
-- put a box around it,
-- put it in brackets, or
-- end it with something like "End Note".
(I looked at a couple other Ecma specs, and there doesn't appear to be a "house style" for Notes.)
actually the ECMA house style for TC39 is basically the ISO/IEC style http://isotc.iso.org/livelink/livelink?func=ll&objId=4230456&objAction=browse&sort=subtype√
because TC39 standards are usually fast-tracked as ISO standards.
In that document ("Rules for the structure and drafting of International Standards"), the relevant section appears to be 6.5.1 "Notes and examples integrated in the text". As far as I can tell, none of the requirements there prohibit any of my suggestions in comment 0.