You'll find this is taken care of in the new 2.6 release that is nearing completion. If you find this to be a real issue, you might insert a "textual" custom field or something to display an instructional note telling users not to do that. You're probably only the 2nd person to even mention that in 3 years I don't think many people would fall into this issue. Regardless, it has been handled. Thanks.
Thank you for your answer! I find this is a real issue, because in this way my customers dont´t need to mark the "general term and conditions" to buy sth. OK, I´m looking for the 2.6 release.