For me, the diaper bag usually stays in the car. If I am wet or messy, I finish up what I am doing and make a mental note to where the bathroom is. Then I will go to my car and I will bring my backpack into the store. I then go right for the restroom. I don't hang out or wander. I am confident and on a mission for the bathroom. If I don't know where it is, then I ask. Maybe I am lucky but despite ignoring many no backpack signs, I have never been confronted about it. Also, I have the mindset that this is a medical thing. I am mentally prepared. If a store clerk was to make a big deal out of the backpack, my response would be I have medical supplies in it and need to use your bathroom. If they keep pestering me about it, then I would offer to leave it upfront and would take my diaper supplies out and would carry them to the restroom. I have learned to leave emotion out of it.