Apparently, there's enough of a problem with nurses reusing plastic syringes — just snapping on a new needle — that there is a campaign forming to speak out against the problem.
The problem is that some nurses thing that as long as you use a sterile needle every time, there is no problem of transmitting disease. This simply is not true. The plastic syringe can transmit disease just as easily as the needle.
This shows how important it is to be in charge of your own diabetes management if you are ever in the hospital. You can — and should — request that you control your insulin regimen. After all, you know more about your body and how it reacts to insulin, sugar, etc. than some doctor who has never met you before!
If you can't be the one in charge of your insulin shots, be sure to confirm with every nurse, every time, that the entire syringe is sterile. It's sad that we have to think about these things while we're in the hospital, but honestly, it's better to harass a few nurses than to wind up with hepatitis C — or worse!