Introductory flights are available and we don't require the guests to
purchase a "membership"; just pay the price for the intro flight.
These flights are made by instructor pilots, but no flight instruction
is provided.

My understanding is that we include a day membership for liability
purposes -- we're now flying a club member rather than providing a
flight for hire. Most of our intro pilots are also instructors, so we
can provide some instruction if the passenger so desires. Canada only
has one class of glider licence, not "Private" vs "Commercial".
And yes, when I said we instruct for free, I meant for the services of
the instructor... the student pays for aircraft rental and tow fees at
regular club rates.