Checkboxes Validation

Hi.

I’ve seen that, editing few line in the alo-easymail_functions.php file, there’s the possibility to show checkboxes in the newsletter subscription page.
But is there a way to validate them?
The ajax call seems just to check for the value of each input, but not for the “checked” property of the checkboxes.
I tried to look at the function but it seems tu redirect to the general wordpress ajax file and I don’t understand how it works.

I just want to add a check to make users accept TOS and Privacy before subscribing to my newsletter. But I need it to be validated.
It’s not usefull if the form is submitted anyway.

Any suggestion?
Thanks.

http://ww.wp.xz.cn/extend/plugins/alo-easymail/