I’ve said it before, but as I can’t seem to remember this myself, I’ll say it again: Mac IE appears to add spaces up to the maxlength of a form field, and at least one space after a hidden form field when submitting. This can cause all sorts of unexpected behaviour when validating the inputted data. So my hearty recommendation to you all? By default, trim all extraneous spaces from form data. I’ve added this pass to my generic validation script now, so hopefully this will prevent me from banging my head against this wall in the future.