To provide the best service to all participants of any seminar or workshop, we keep the numbers of participants small (max 12). This gives us the opportunity to respond to each participant. Early "blind bookings" with the option to withdraw later and at will leaves us - as the organizer - not only with empty places, but also with an overhead on costs. With this scenario nobody can make a proper calculation.
But even worst some very interested practitioner will miss out on the event, because the bookings reached the limit. If short before the start of the event cancellation come in, most practitioners are not in the position at "stand-by" to book for their office, flights or hotels.