Thanks for letting me know. 
How would you feel about adding #to_i to Date? 
```ruby
def to_i
  in_time_zone.to_i
end
```
This way #seconds_until_end_of_day will use the same logic as Time and DateTime and will return 86399 for the answer (which is consistent with Time#seconds_until_end_of_day behavior for a certain day at midnight)