Devil's advocate: If supplying an email address opens up a 30 day free trial, you can hardly complain when people do supply email addresses... especially when, to smooth the experience, there is absolutely nothing else but a email address field and a "start free trial" button.
People will always find ways to use things to the limit or abuse them. You need to consider where to put the limit to balance user experience vs. preventing abuse.
People will always find ways to use things to the limit or abuse them. You need to consider where to put the limit to balance user experience vs. preventing abuse.