Conceptualize it as a three-point scale of trust:
1: I will fly with you.
2: I will fly with you without even wearing shoes. (Realistically, I can't imagine why shoes would make a difference.)
3: I would let my family fly with you.
If you say you wouldn't put your family in a Max, then your trust in the Max is not at level 3. Logically, this is a very weak constraint; it only shows that trust < 3. Maybe trust is 2. That's what fingerlocks is saying.
However, vernacular language generally doesn't work that way. A common mode might come from the following train of thought:
- I don't trust this plane.
- How much do I not trust it? The MAXIMUM LEVEL, LEVEL 3!
- "I would not let my family fly on this plane."
Here, from a logical perspective, the person has confused "lack of level 3 trust" with "level 3 distrust". This is bad in a math class (the scope of the negation is wrong -- [not [level 3 trust]] vs [level 3 [not trust]]), but routine in ordinary speech.
