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.

Thanks!