Would be a good idea to forbid SI-units to be used by US-friendly nations:

first it would conveniently pre-tag all others for arresting and questioning

second it might keep one or another Space Shuttle from blowing up because fuel tank washers will be precisely fitting when engineers cannot mix-up the housewive stuff with the then evil world units.

What about replacing the 4 f. oz. rule by 8 tbsp., probably those TSA guys can figure that out better?

Beware, US tbsp are different from metric tbsp!!

see: http://www.convertworld.com