Spam complaints may be rare nowadays however, if you get one it can cause you and/or your host some misery. The best way to get over this problem is to have concrete proof that the person who made the complaint genuinely subscribed from your site.

Personally, I use an autoresponder service so the web form generator automatically adds code that grabs the visitor's IP address and date/time stamps the submission. Instead of receiving a mail to let me know someone just submitted my form, I get one as shown in the attachment.

It would be nice if such functionality could be added to the Email forms generated by X5.