Maybe you can convert your requestors result into List<> then add what you need to show and then return.
For example :
public IEnumerable<Person> GetRequestorEmail2()
{
List<Person> personList = new List<Person>();
personList.Add(new Person { Something = "asd", Something2 = "0" });
personList.Add(new Person { Something = "asd", Something2 = "1" });
personList.Add(new Person {Something= "<-Please select Requestor->", Something2="-1"});
return personList.OrderBy(x=>x.Something);
}