When strangers call you 'mom'
Yesterday DH and I were at church with SS8 and SS5. A woman we don't know was making casual conversation and asked me "well, mom how are you feeling about kids back in school now?" She was referring to me as "mom" and SK's were right there. The assumption that I am BM is natural, and happens often at restaurants, parties, etc where other folks don't know our family dynamic (or family drama) but I'm not always exactly sure how to handle it. Do I correct them (as I did in this situation by saying, "well actually I'm their stepmother"), or just let it go, or does it depend on the specific situation?
I love my stepkids very much, and they love me (for now), but they also love their BM and she makes no secret about feeling that I am not someone they should feel any connection toward. I don't want them to feel as though I am rejecting them (ie "They are not MY children..") but I also don't want them to think that I am trying to take over. I imagine this happens to other SM's as often as it happens to me. What do you do?