Thanks to everyone for their comments on this question. Like many, I don't understand how anyone can hand sew without a timble to protect their finger. Now I'm making judgment based on my ability. However, I face this every time I teach a hand quilting class. There have been several ideas that I will pass along. I learned to use a thimble many many years ago when I was in the Army and sewing patches on my shirts. I had a little portable sewing kit and it had a plastic thimble in it. I am sure my fingers would never have healed if not for that thimble.
I realize some can and some can't. It is second nature to me now. Like any tool or gadget some work and some don't. I have an assortment of the aids that students can try. And I'll keep trying to teach those who can't.