My policy is to leave them alone. When I was much younger I saw a beautiful shell of a snapping turtle. I went closer to investigate and was horrified to find an empty shell with skin and blood kind of pooled in it. I know they were making turtle soup but maybe they could have cleaned up the shell to use for an art project...or bag it so little girls don't have nightmares.
I'm glad to know you have all your digits and your knowledge and love of nature makes me feel confident that you would do no harm to those creatures. <3
A shell can certainly be beautiful.... or disgusting...
Though I sometimes give them to people for soup, I like to let them go.
If there are more out there now, there will be more when my kids grow up, and then they can show their kids, (and tell lots of crazy stories about what their dad used to.)