Never had something like this happen to me, but if I saw my ATF at the grocery store I would just make eye contact and smile and say hello. I would not offer to pay her groceries, or approach her in any way...much less follow her....that would be creepy. I think she makes her own money, deserves her privacy and to be respected like anyone else. Now if the situation was reversed and my ATF saw me, it would be awesome to get the attention, but I would not expect anything else. Either way, it would give us something to talk about during our next encounter