Is it possible to make the public comment field of the rsvp optional? How can did be done?

Actually I was able to change that.  If you edit the EventRSVPEdit.ascx file and simply change the RequiredField parameter to false that'll fix it.  Code section below:

<tr>

<td class="subhead" valign="top"><dnn:label id="pllblComment" suffix=":" controlname="lblComment" runat="server"></dnn:label></td>

<td><st:smarttextbox id="txtComment" runat="server" width="400px" TextMode="MultiLine"

Rows="4" RequiredField="True" ClientValidation="true" text="" MaxLength="250" IncludeMessageLineBreak="False"

DisplayAsterix="True" MinMaxDataType="String" MandatoryLanguageStringCode="" />

<asp:regularexpressionvalidator id="valMaxLengthCheck" runat="server" ControlToValidate="txtComment" CssClass="FieldValidationMessage"

ValidationExpression="^[\s\S]{0,250}$" resourceKey="valMaxLengthCheck" /></td>

</tr>