Or you could simply disable it until you are ready -from site admin>courses>enrolments
Thanks Mary - I did try some editing on that page, but I get what sounds like a known bug - missing string errors any time I change any language. (http://tracker.moodle.org/browse/MDL-19896)
I could disable PayPal, but I was trying to use the same screens to say "pay by check" since these screens show the course cost quite nicely!
there is an additional enrolement process that creates invoices. http://moodle.org/mod/data/view.php?d=13&rid=1693&filter=1
If the money came in, you can add it to Moodle and the participants get course access. We've used this feature several times for large congresses and it works perfect.