create table events (
    id integer primary key,
    name text not null,
    event_date text not null check (
      -- YYYY-MM-DD
      event_date glob '[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]'
      and date(event_date) is not null
      and date(event_date) = event_date
    )
  );

  sqlite3.IntegrityError: CHECK constraint failed:
    event_date glob '[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]'

I see. The strict tables page did not mention the date and time functions.

Python would show the 1st line always? Or the failed part?

This is unreasonable for a very common type I think.