As a point of interest it is actually possible to tell whats being typed once a typewriter machine is a little older as a microphone and digital sampling can work out the difference in the sounds the keys make on the paper, a golfball model thus makes perfect security sense as its extra noise makes it too hard to parse the noise of the motors from the keystrike noise.
The sounds of older machines can be recorded and due to the fact that repeated pressing of the same key cause mechanical wear and tear the levers shift slightly as does the print head with time, using simple analysis of frequency of letters its possible to tie the keystrokes up to an individual character, so older types of machine would definitely not be such a good idea.
I wonder how much money would be saved if all governments stopped being so selfish and underhand.