It worked well.
Life circumstances change, however. For us buying a hybrid car has made the convenience of being a member of car sharing program redundant.
I searched the Zipcar web site for membership cancellation information. This is not mentioned under the "help". But, type "cancellation" in the "Ask a question box", and you get
We're sorry to see you go! To cancel your membership, please give us a call below.
I called today, and here is the scoop. Two things should be in place for a full membership refund to occur:
a. No reservation should have been made, and used in the current membership year
b. Cancellation should occur less than 30 days after the membership renewal date
So, I still enjoy carrying my Zipcar membership around, at least for a few more months!