Membership Plugin allows joining without paying


I'm in the process of setting up a "Friends of" group for as charity site using the membership plugin but during testing I have found that if you go through the registration and join procedure but cancel the payment before entering your paypal password (therefore not paying) you still get full membership.

While the object for us is to create a membership list and not necessarily raise funds (we have the same level membership for free for under 18s and unemployed) we would like to know who has paid and who has free membership.