I always baffles me when I encounter a service that uses a different validator for sign up than sign in. Firstly, why write this twice. Secondly, it can cause so many headaches.

the one I run into a lot is a + in an email address.

I like to use them on sites I think will likely sell my email address so I'll do something like "my.normal.email+websitename@gmail.com"

I rarely have trouble signing up with this email address, nor verifying it, but then you go to login and splat.

but not properly escaping the lastname of "true" just seems way to basic for a service as large as icloud.