Who would make up the research team for a trans-Atlantic tunnel?

Not anymore than airlines are today. To go on it or send something through it, you or what you're sending would need to go through a security screening process. Just as with airports, it all would depend on the screening process ... which would naturally need to be part of the design of the system.

Scott Jensen

No way.. ;)

The tunnel would also be vulnerable from outside attack as well. But the logistics of a water wouldn't be easy either..

Except you would also have thousands of miles of ocean to patrol as taking out the tunnel from the exterior would likely not be too difficult.

Depth of the tunnel may discourage terrorists. They probably don't have the capabilities to go too deep.