We could...as we give tremendous benefits above and beyond all others who do charge a yearly fee...
Loyalty Rewards Membership Programs Free versus Fee- http://www.paytronix.com/media/4399/art_freefee.pdf
Free Versus Fee: Why Consumers Will Pay For Loyalty Programs https://www.claruscommerce.com/blog/free-versus-fee-why-consumers-will-pay-for-loyalty-programs/