That is a really crappy analogy. The odds of getting shot in a theatre are .000000000000000001 to 100: far less than dying on a commercial flight.
Outlawing guns at the movies seems to be even more reasonable than outlawing passengers boarding with a parachute strapped to them.
You have done the math , and I like how you have done it.
The odds of dying in a plane crash are actually only applicable if you are riding on a plane.
And the odds of being attacked at a theater only apply if you are attending a theater.
If your carryon baggage includes a parachute , the pilot might think you are emulating D.B.Cooper, so the odds are that the pilot will refuse to lift off.
What are the odds that you may be killed in a crash , including all types of crash?
What are the odds that you will be attacked , including all sorts of assault?
Would it prevent a lot of crashes to forbid airbags in cars?