I wanted this feature on the Mac for my daily checklists - it's good to check off each item as I go through, but a pain to have to uncheck them individually the next day. it doesn't look like it's likely to arrive as a built-in feature for the Mac client, so I wrote a quick AppleScript to do it, which seems to work well.
tell application "Evernote"
set theNotes to selection
repeat with theNote in theNotes
set noteHTML to (HTML content of item 1 of theNote)
set noteHTML to my replace_chars(noteHTML, "en-todo-checked", "")
set (HTML content of item 1 of theNote) to noteHTML
on replace_chars(this_text, search_string, replacement_string)
set AppleScript's text item delimiters to the search_string
set the item_list to every text item of this_text
set AppleScript's text item delimiters to the replacement_string
set this_text to the item_list as string
set AppleScript's text item delimiters to ""