Coupons in Membership

I do not see any place to disable Coupons from appearing above the subscription options on the registration page.

I have modified the subscription.form.php to remove the feature but want to avoid having the file overwritten every time we apply a Membership upgrade.

Is there a better way to approach disabling Coupons?

If not, can we can please add a feature to make coupons optional. When one’s memberships literally cost thousands of dollars for training and website membership, we do not want people searching for coupons that do not exist.