Yes, this is the reason I know that the + character is %2b in a url. I've had to manually type it on so many crappy unsubscribe links (they don't realize + needs to be escaped because the web server they are using is doing the old-school + => space translation).

The nice thing about running my own email server is I configured it to use . and _ as well as +. [email protected] and [email protected] are pretty much guaranteed to work, and it ends up exactly the same as the +.