What would you do?

It looks like it is going to be a most unpleasant day to drive. Rain and wind are forecast in every direction. The severe weather that hit the Great Plains yesterday will visit the Ohio Valley and Great Lakes today. We don't need the rain, my yard is like a bog as it is. My flower beds ate quickly becoming weed beds. I haven't had time to pull, chop, or spray the various unwanted greenery in preparation for planting some flowers. It has been too cold and wet to plant anyway.

Here is a conundrum for you. I'm really interested in your feedback. A local pizza place has a Yelp (insert appropriate trademark here) coupon that states you can get a large pizza for $10. They routinely take $10 off the pizza. The coupon is very clear on the deal. Do you tell them of the mistake or just chalk it up to good fortune if you get a great deal? About fifty percent of the time we go there they ring the pizza for $10 off. Even the manager has made the mistake. What would you do?