One of the things I am learning with my kids is how I tend to not always know what sensory needs will strike and when it will happen. (I tend to not stick very well to routine or a schedule which isn't a task that kids like mine tend to handle well.) One day I was in the fabric store and I had already gone through my purse. I had taken out toys, pens, and whatever else I had stuffed in there and yet my kids were still putting their hands on EVERYTHING. Being in the checkout line I began handing them things that were in the cart and telling them I needed their help holding things. Slowly my cart emptied as their hands and arms got full. Customers in the checkout line began grinning as they understood what I was doing as they had seem them grabbing things off shelves and hooks moments before. Finally, their arms and hands were full and they couldn't get into anything and I was at the front of the line and able to help empty their arms and put my purse back into some sort of order.
It did work quite well at the drop of a hat. Maybe this is something that will help you out when you end up going out unprepared. I do admit having a 10 month old I make sure my keys have toys or objects on them which sometimes the older kids do play with. Fisher Price has made some of their old toys into key chains and there are all sorts of things that light up as well as koosh balls too which give great input.