“We're doomed to repeat the past no matter what. That's what it is to be alive. It's pretty dense kids who haven't figured that out by the time they're ten.... Most kids can't afford to go to Harvard and be misinformed.” 
― Kurt Vonnegut Jr., Bluebeard

On Tue, Sep 5, 2017 at 9:02 AM, Random832 <random832@fastmail.com> wrote:

As for email, the email standards don't make any guarantee that the
username portion of addresses will be case insensitive. 
Actually they do, RFC722 was not quite as crisp as this which 833 replaced, but even with 722 the intention was pretty clear and examples described "case independence of certain special atoms."   With 833, Crocker cleaned up the language to be simply:

From RFC833, Section 3.4.7 CASE INDEPENDENCE

Except as noted, alphabetic strings may be represented in any combination of upper and lower case. The only syntactic units which requires preservation of case information are:
  • text
  • qtext
  • dtext
  • ctext
  • quoted-pair
  • local-part, except "Postmaster"
   When matching any other syntactic unit, case is to be ignored.