Replace expectation about the instrument being accessible with a back…

…ground note

_rules/audio-or-video-avoids-automatically-playing-audio-80f0bf.md

@@ -55,14 +55,10 @@ This rule applies to any `audio` or `video` element for which all the following
 - **not paused**: the element has a `paused` [attribute value][] of `false`; and
 - **audio duration**: the element has a [media resource][] for which the audio output lasts more than 3 seconds.
 
-## Expectation 1
+## Expectation
 
 For each test target, there is at least one [instrument][] in the same [web page][] to pause or stop the audio, or turn the audio volume off independently from the overall system volume control.
 
-## Expectation 2
-
-The [instrument][] to pause or stop or turn the audio volume off is [visible](#visible), has an [accessible name](#accessible-name) that is not only [whitespace](#whitespace), and is [included in the accessibility tree](#included-in-the-accessibility-tree).
-
 ## Assumptions
 
 This rule assumes that the [mechanism](https://www.w3.org/TR/WCAG21/#dfn-mechanism) to control the sound must be located in the same [web page][]. Mechanisms located on other pages can still create accessibility issues for users relying on sound to navigate (e.g. screen readers users) since the autoplaying sound will interfere with their ability to find and activate the mechanism. If a [mechanism](https://www.w3.org/TR/WCAG21/#dfn-mechanism) external to the [web page][] is provided, it is possible to fail this rule but still satisfy [Success Criterion 1.4.2 Audio Control][sc142].
@@ -77,6 +73,8 @@ The native `video` and `audio` controls in several browser and assistive technol
 
 ## Background
 
+The [instruments][instrument] used to pass this rule (if any), must meet all level A Success Criteria in order to fully satisfy [Success Criterion 1.4.2 Audio Control][sc142]. These extra requirements are left out of this rule, and should be tested separately.
+
 - [Understanding Success Criterion 1.4.2: Audio Control](https://www.w3.org/WAI/WCAG21/Understanding/audio-control.html)
 - [Accessible Multimedia](https://developer.mozilla.org/en-US/docs/Learn/Accessibility/Multimedia)
 - [Failure of Success Criterion 1.4.2 for absence of a way to pause or stop an HTML5 media element that autoplays](https://www.w3.org/WAI/WCAG21/Techniques/failures/F93)