RadioButtons causing built-in .net form validation to malfunction - asp.net

Question

I have a very basic form in a .Net page, it has 6 fields each with a requiredfieldvalidator attached. Everything works fine and the form is stopped if even one field is blank. I was asked to add a section with 2 radio buttons (I set one option as checked to avoid any validation on the field), now the form submits no matter if the fields have information in them or not.
Subset of default.aspx
<form id="form1" runat="server">
<div style="margin-bottom:10px;">
<label for="txtAgencyName">Name of Agency</label>
<asp:TextBox ID="txtAgencyName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvAgencyName" runat="server" ErrorMessage="*Required" ControlToValidate="txtAgencyName" ValidationGroup="vg1" CssClass="rfvErrors"></asp:RequiredFieldValidator>
</div>
<div style="margin-bottom:10px;">
<label for="txtEmail">Email Address</label>
<asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvEmail" runat="server" ErrorMessage="*Required" ControlToValidate="txtEmail" ValidationGroup="vg1" CssClass="rfvErrors"></asp:RequiredFieldValidator>
<asp:RegularExpressionValidator ID="revEmail" runat="server" ErrorMessage="Invalid Email Address" CssClass="revErrors" ValidationExpression="(^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*#([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})$)" ValidationGroup="vg1" ControlToValidate="txtEmail"></asp:RegularExpressionValidator>
</div>
<!-- This is the section that is breaking the validation -->
<div style="margin-bottom:10px;">
<asp:RadioButton ID="rbOwnershipAgent" runat="server" Checked="true" GroupName="Ownership" />
<asp:RadioButton ID="rbOwnershipReferral" runat="server" GroupName="Ownership" />
</div>
<!-- --------------------------------------------------- -->
<div style="margin-bottom:10px;">
<label for="txtAgencyContact">Agency Contact Name</label>
<asp:TextBox ID="txtAgencyContact" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvAgencyContact" runat="server" ErrorMessage="*Required" ControlToValidate="txtAgencyContact" ValidationGroup="vg1" CssClass="rfvErrors"></asp:RequiredFieldValidator>
</div>
<div style="margin-bottom:10px;">
<label for="txtPhone">Telephone Number</label>
<asp:TextBox ID="txtPhone" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvTelephone" runat="server" ErrorMessage="*Required" ControlToValidate="txtPhone" ValidationGroup="vg1" CssClass="rfvErrors"></asp:RequiredFieldValidator>
</div>
<div>
<label for="ddlState">State</label>
<asp:DropDownList ID="ddlState" runat="server" AppendDataBoundItems="True">
<asp:ListItem Text="Select State" Value=""></asp:ListItem>
</asp:DropDownList>
</div>
<div style="margin-bottom:10px;">
<label for="taCarriers">In your agency, who are the carriers writing liquor liability for you today?</label>
<asp:TextBox ID="taCarriers" runat="server" TextMode="MultiLine" Rows="3"></asp:TextBox><asp:RequiredFieldValidator ID="rfvOtherCarriers" runat="server" ErrorMessage="*Required" ControlToValidate="taCarriers" ValidationGroup="vg1" CssClass="rfvErrors" style="margin-top:15px;"></asp:RequiredFieldValidator>
</div>
<div style="width:100%;margin-top:20px;border-bottom:1px solid #27a0d6"></div>
<asp:Button ID="btnSubmit" runat="server" Text="Submit »" name="bnSubmit" class="submit" ValidationGroup="vg1" />
</form>
Am I missing something simple as far as an attribute on the submit button or radio buttons? I'm just surprised that a built in .Net control is causing this kind of trouble for something this basic. Thanks for any help.