Actually, yes. If you are using the program legitimately to invite people, you won't even notice them, but here's the fine print: You cannot invite yourself. You cannot invite anyone who uses the same credit card as you do. You cannot invite someone who uses the same mobile device as you.
Referral policy: Feel free to share your invite code with your friends via email, Twitter, Facebook, personal blogs, etc. where you are the primary content owner. However, you cannot distribute your invite code on sites where you are a contributor but not the primary content owner (e.g., Wikipedia, app stores, coupon websites) and you cannot promote your invite code via Search Engine Marketing (e.g., AdWords/Yahoo/Bing).
If you break any of these rules, the Insider777 Grinch may take all of your credits or coupons away, and/or suspend your account.