lucy24 - 9:52 pm on Jul 26, 2013 (gmt 0)
I think about when I email a link to somebody, I usually paste the link, then immediately follow it with a period, comma, etc. I don't know how easy it is for a software to mess that up and lump the punctuation in with the link.
That's a good point. It happens all the time with auto-generated links in some forums: once you've met http: or www. the auto-linking continues to the first space. And then you really do get a 404 if there happened to be punctuation at the end. But the problem tends to be with longer more complicated links, not the bare domain name. And you've got code for those longer links.
The googlebot does a lot of weird things but I don't think it ever asks for URLs with gratuitous trailing punctuation; when there is punctuation at the end, it's obviously from someone else's link.
I thought of that but didn't think it could possibly work
Well, don't take my unsupported word for it. Report back, one way or the other, and then everyone will know for sure.