In plain language
Anything that moves, blinks, or auto-updates for more than 5 seconds needs a pause/stop/hide control.
Who it affects
People with attention disabilities, low vision, or screen-reader users who lose place when content moves.
How to check
List all carousels, tickers, animations, auto-refreshing widgets: each needs a working, keyboard-reachable pause or stop. Worked example — A used-car marketplace's listing filter: watch any auto-updating feed (stock ticker, live scores, chat): if it updates continuously with no pause or frequency control, it fails.
Common misconception
An auto-rotating carousel with a pause button that only appears on hover doesn't count. The control needs to be permanently visible and reachable by keyboard, not a hover-only extra. Real example: on a weather app's forecast screen, scrolling or moving content (ticker, marquee, slider) runs automatically with no pause/stop/hide button.