I agree that anyone can be a crime victim at any given time. That said, I think one owes it to him or herself to try decrease the odds of him/herself being victimised by criminals. I use to take night walks at the Huntington Beach beachfront when I first moved to SoCal, but I remember the stabbing of a jogger there many years ago, and now I don't do it anymore.
My main points are these:
i)I have seen shady characters on the SART at daytime, and I really cannot say what can happen when it's dark. I once saw a guy deliberately break bottles on the SART bikeway, and I really do not want, nor wish to find out what this kind of person can or will do when it's dark.
ii)There is a drug pandemic out there, in case no one has noticed. I suppose not all drug addicts are prone to criminal behavior or violence, but some wouldn't think twice about mugging a cyclist or some old lady so as to enable a quick "fix".
In conclusion, I submit that one should try all one can to not place him/herself in potentially "dicey" situations.
I say ride the SART daytime, and the streets at night.
Regards,