1. In a crowded elevator
2. On a crowded bus
3. In a public library
4. While on a date
5. While giving a speech
6. In church
7. In a crowded classroom
8. In your office when you're alone - someone's bound to walk in immediately afterwards
9. In a movie theater
10. In your cubicle at work - again someone's bound to walk in to visit
11. In a walk-in freezer - it'll linger a while
12. In an commercial airplane
13. On a ticket line
14. In your car before picking up a family member
15. In a Cessna

you've tried and proven all of these, haven't you?