The Occupational Safety & Health Administration is currently in the process of proposing updates to current standards across the board. The changes that are proposed will update outdated, duplicate, or inconsistent standards.
One of the proposals is to remove the word "unexpected" from the current Lockout/Tagout standards. The reason being that employers often effectively use this word to defend themselves from citation or penalties based on this word.
OSHA's current standards require employers to protect their workers from potentially hazardous energy sources while working on equipment. They hope to continue to protect workers by removing this word.