Acceptable: Asking if you're interested in their credit card at the entrance, and leaving you alone when you politely decline.
Not acceptable: Following me into the produce department and tapping me on the shoulder as I'm trying to choose peppers, then persisting in bothering me even when I say I'm not interested. I don't want more credit cards and I don't care if I supposedly get free groceries. I said I wasn't interested, so please leave me alone!
This has happened to me twice now, once at Zehrs, and once at Superstore, and I swear it was the same woman both times. Yet another reason for me to not shop at Loblaws-owned stores.