No. Just... no. Styaying safe while navigating through a complex, living, breathing, dynamic environment where one wrong move could kill you requires a VERY high level of awareness of your surroundings. Part of that includes depth perception. So putting a mirror in your peripheral vision that you look to before, say changing lanes, is incredibly dangerous. You know the saying, objects in the mirror may be closer than they appear? If you're not using your eyes, your ears, or other means of gauging how fast a car is travelling based on engine sounds, depth perception, a good sense of your own speed -- essentially relying instead on a mirror that simply cannot give you a good idea of how to time your movements through traffic -- not to mention adds visual noise to your periphal vision.

I could go on about it but... just... no. Don't put mirrors on Citibikes. It's just asking for trouble, especially from inexperienced cyclists or people who typically change lanes without visually checking the blindspot EVERY time they change lanes.