Judah wrote:

1 - TSRs _only_ impact law abiding people. Circles on a sectional will
not stop someone out to kill themselves.

True for small TFRs like the stadium TFRs. But not true for the ADIZ and
larger TFRs (like 30NM Presidential ones). If a controller sees a 1200
squawk within 30NM of Washington, DC, what do you think happens next?

Why do you believe that someone bent on harm would be dutifully
activating their transponder and squawking 1200, flying a plane
with a large primary radar footprint, or flying in a manner which
would make them straightforward to intercept in less than 10
minutes?

What "restrictions" could they possibly put in place to effectively
prevent a "GA suicide bomber" anyway?

How about metal detectors and airline-style security systems in all
airports? Or Permanent Flight Restrictions in the areas that are now
Temporary, or more ADIZ Zones preventing GA pilots from flying over
populated areas without discrete transponder codes and two-way
communication with ATC?

These are examples of more restrictions which would impact only law
abiding people without effectively deterring someone bent on harm.

Cheers,
Sydney