I have found that restricting Body Armor is more effective than restricting weapons, especially in Traveller. Further while wearing Body Armor might be legal, it might also be socially unacceptable. Most body armor is noticeable and difficult, by its very nature, to conceal. Where you might be able to conceal an SMG, you are going to be noticed wearing that Combat Environment Suit. And wearing such a thing, depending on the world of course, might be gauche.
Further bodyarmor would generally be frowned upon in most business establishments, particularily bars. As the environment will tend to take more damage than the people in a bar fight, and bar owners, would typically take a dim view of that. Since that is where people tend to socialize, the effect would carry over to other parts of the social world.
This would have a secondary impact on what the military and law enforcement might wear, and not just off duty. When the fecal matter is not impacting the rotating propeller, even a military patrol would tend to be less armored and off duty individuals would be unarmored or lightly armored, depending on local custom. After all they generally want the locals to be firendly. (It helps to gather information among other things.)
Riding as a passenger on a starship would be similar. Don't just lock up the weapons, lock up the armor as well. (Though Vaccsuits can act as armor so a compromise has to be reached here.)
As a GM this also makes your characters less prone to just try to shoot there way out of trouble.
