I mean first you have to get caught. Is your friend coming up to you register and you're putting in your discount for them? It's tied to the Circle app, so youll have to scan yours (which the eye in the sky will definitely see) and if they're paying it'll be with cash, they can't use their Circle app to pay for it or use a credit card. (Unless you use cash a lot to pay for things the transaction will probably be flagged as suspicious, cueing a review of camera footage).
If you buy something for a friend and use your discount once in awhile it can be a "gift" and that's acceptable, as long as they don't pay you back for it (but if it's infrequent enough who would ever know if they did?).
You could run into trouble if they have to return it though, it would show your team member discount on the receipt.
If your "friend" is actually your long-term romantic partner, there is a "domestic partner" option under team member discounts. In case it applies.