People Picker not allowing empty value to be stored

Hello, I am trying to resolve an issue with the People Picker control.  I have an ASPX page that is used to display a table of bunch of users.

For example:

Essentially this page loads and populates this row with data that is saved in list.  THe idea being that the user then can change anyone one of these fields if necessary.  The problem comes in that it appears the People Picker caches the value, so if simply select "Eckert, Mark" above and delete it, the value is still stored in the people picker TextArea in the HTML.  I found this out by using the IE developer Toolbar.

For example,

Also, this is the way I create my PeopleEditor objects:

                           PeopleEditor MemberName = new PeopleEditor();
                            MemberName.ID = "peMemberName" + i;
                            MemberName.Width = Unit.Parse("225px");
                            MemberName.MultiSelect = false;
                            MemberName.AllowTypeIn = true;
                            MemberName.AllowEmpty = true;
                            MemberName.SelectionSet = "User";
                            string strAccount = GetColumnValue(drTeams, "Member");
                            MemberName.CommaSeparatedAccounts = strAccount;

Does anyone know a way around this?  I have a requirement that the People Picker control must be able to be edited and persons removed (left blank if needed.)  Thanks a lot, mark