How can I make a SafeCracker contact form POST only (no editing) in EE 2.2.1?

I have a simple contact form that works well. I only want people to be able to POST the form and do not want to allow editing. I use SafeCracker for the forms. How can I do this as the Channel/Member Group only as a permission for allowing POST and EDIT together? If I setup the form without the VALUE field, will that be enough to disallow editing like this example?

{exp:safecracker channel="contact_form" return="contact/thanks" } 
<input name="title" type="text" /> 
<input name="my_custom_field" type="text" /> 
<input type="submit" value="Submit" /> 
{/exp:safecracker}

I see other examples have it setup as you see below which looks like it is editable. Do I just need to remove the VALUE parameter to disallow editing?

{exp:safecracker channel="contact_form" return="contact/thanks" } 
<input name="title" type="text" value="{title}"/> 
<input name="my_custom_field" type="text" value="{my_custom_field}" /> 
<input type="submit" value="Submit" /> 
{/exp:safecracker}

Thanks in advance.