Hi Ally:
I believe you can go to the Spit now whenever you want, at least during daylight hours. And whenever you go, you'll be sure to see dozens of other people, dozens of other birders. Good luck.
You raised a good question about the Purple Sandpiper--if it had a look of sadness in its eyes. I think the bird probably participates in what the novelist Emile Zola called "la tristesse muette des choses"--the silent sadness of things. Zola thought this sadness appeared not just in the eyes of animals, but in many of those things that science tells us are insensate but that we suspect really do have a life of their own--discarded Christmas trees, an old pair of boots, an empty wine bottle standing upright on the street corner, books gathering dust on a shelf, an uninhabited house on the side of the road, a piece of tinsel in the grass. It was perceptive of you to see that quality in the eyes of the bird--I'm glad to hear that the photo succeeded in capturing that.