They must be tough if they can share needles. Wouldn't it be dull after going through the skin and smart like all get out? Low dead space is intended to save medicine.
I know the majority of IDU in my local area, and thankfully sharing equipment just isn't a thing that happens. In the 6yrs or so that I've been interacting with users, I've never seen a situation where it was going to happen. In the relatively affluent area of Stockport, users would rather smoke it than take the risk of sharing equipment!