What the standard says
If a keyboard shortcut is implemented in content using only letter (including upper- and lower-case letters), punctuation, number, or symbol characters, then at least one of the following is true:
Why it matters
Speech-input users emit stray characters constantly. A bare "s" shortcut fires while they are dictating.
What a failure looks like
- failsA single-key search shortcut with no way to disable it.
How to fix it
- doRequire a modifier (Ctrl, Alt, Cmd), or only listen while the relevant control has focus, or let the user turn shortcuts off.
How A11ySignal checks it
manual
No automated rule can judge this criterion, and we will not pretend otherwise. A clean scan does not mean 2.1.4 passes — it means nothing we can measure fails. This one needs a person.