In plain language
Single-key shortcuts (letters, numbers, symbols) must be off-able, remappable, or active only when the control has focus.
Who it affects
Speech-input users and people who press keys accidentally.
How to check
Press single letter keys while browsing (not in a text field): if anything fires, look for a setting to disable or remap it. Worked example — An insurance company's claims form: open the remap UI and try assigning a shortcut using Ctrl/Alt/Shift plus a letter: if it only accepts a bare printable character with no modifier option, it fails.
Common misconception
A single-letter shortcut like “j” for “next” feels like a nice power-user feature until someone using speech-to-text dictates a sentence containing that letter and triggers it by accident. Real example: on a news outlet's article page, single-letter keyboard shortcuts (like 'j', 's') can't be turned off or changed — speech-input users trigger them accidentally while dictating.