Affiliation field without default takes first entry as default

When an Affiliation enrollment attribute is added to an enrollment, but no default set for it, the generated select element does not properly display a 'Please select an affiliation' entry, but only displays the set of valid affiliations and, due to browser implementation, automatically selects the top option.

Less attentive users take this as being correct and are not pressed into actively selecting an affiliation from the list of possibilities.