If the entry signal looks like waving hello, engagement will open while nobody meant to interact

What it is

If the entry signal looks like a living wave, nod, hair-adjust, or point-at-someone, engagement will open when nobody meant to interact, and Midas touch moves from the command layer up to sign-up. High distinctiveness means, on the target scene's living-motion set, this signal's false-open rate is low enough to ship. It need not be a secret handshake, but it must not be greeting or shooing a bug. Entry is more dangerous than a command: a command at least sits inside an already signed-up session. A false entry turns every later living motion into a command.

Why it happens

Entry is the session's first classifier. Its negatives are all living motion, not the other commands in the vocabulary. That negative distribution is extremely wide, so the entry shape must sit on the tail of living motion: an uncommon pose, a two-hand combination, or a physical key. “Wave at the screen to start” makes the most common living move the key. Wake words have the same structure acoustically, avoiding coughs and television lines; mid-air entry must avoid social gestures. Distinctiveness fights learnability: the more artificial, the fewer false opens, the harder to remember. The choice is between living false-opens and memory load, not “make it more natural.”

Studying it

Collect living motion in the target scene (talk, walk, chores, pointing). Run entry detection without briefing the entry vocabulary, and get false-opens per hour. Then measure intentional-entry success and time. Draw the false-open versus missed-entry curve. Put candidate entry signals (wave, offered palm, two hands together, key) on the same living set. Collect a separate social bin, because greetings explode wave-like false opens. Do not use laboratory sitting-still as the negative set.

Where it stops holding

A closed desk, one person, a still background, has few living negatives, so wave-to-enter looks fine until it moves to a living room. Key entry gets its distinctiveness from physics and is not under this mid-air distance constraint. Children and pets contribute motion that is not in an adult vocabulary; test entry on them separately. If the entry signal shares a shape with a command, producing the command re-signs or cannot open listening; the two must differ. Greeting gestures in a culture are high-risk negatives; distinctiveness must be remeasured when the market changes.

Applying it

• Write the ship gate for the entry signal on false-open rate against a living-motion set, not on intentional-entry success.
• Prefer a physical key or a pose rare in life. Treat “wave to start” as a high-risk default.
• The social bin (greet, point, clap) is mandatory. If that bin explodes, change the signal; do not crank a threshold.

Related

• Same group: C4.15.1 Engagement needs a user-executable explicit signal · C4.15.3 The entry signal itself needs immediate feedback that listening has started · C4.15.4 An entry that is too heavy cancels the contactless advantage over touch
• Adjacent: C4.02 The Midas touch problem · C4.05 Three dimensions of gesture evaluation
• Search: wake false positive · living motion · distinctive clutch