I would have done the same thing. Ignored, and blocked. the fact she changed her name totally, and didn't mention who she was, as in, "I used to be known as so and so, but am now this and that" is a bit odd. I know when I've sent friend requests to people I haven't seen, say from HS or college, i always send a quick note wiht it, like hey, how are you, so happy to see you on FB, hope all is well, and let them decide if they want to accept or not.
I've also toyed with the idea of friending a couple of ex-BFs, but in the end, decided that while my only intention is to say hi, what's up, and catch up, as they both are married, it might come across the wrong way, so I've held off.