"Select Type" defaults to blank and not shown as required on Availability Search form

Updated: Comment #N

Problem/Motivation

When a user attempts to book a room, the "Select Type" selector defaults to a null entry in the #options array. It is not marked as a required field, yet the submission will fail if a valid selection is not made.

Proposed resolution

In rooms_booking_manager.availability_search.inc, on line 163:, the options array is started with a null item:
'#options' => array('' => '') + rooms_unit_types_ids(),

Chances are, I'm missing some legitimate rationale for doing this, but when that null item is removed and the line changed to :
'#options' => rooms_unit_types_ids(),
the results are more in line with what I'd expect and my client desires.

There is also the issue of this form element not being flagged as required (no red splat), when it actually is .

I'd love to know the reason for this method, or, have a 'fix'.

Thanks!