Not if they're using a membership. They'll only see a discounted amount if they're paying with a card.

So if the customer is self serving when registering for a class and has some remaining class credits, they'll need to click 'Book without membership' to see the discounted rate.

Hosts often use price rules to give discounts on drop-in prices to members that run out of credits. So, if they don't see an option to use their membership, they can always click Book without and still get a discounted rate until their membership re-adds credits.