I imagine that question is not unique to this product. Your award would already have been issued based on the flights you had planned to take. If you miss one, the question is not whether it's a stopover, but rather what is the airline's obligation to accommodate you at all. As brp points out, if you show up within a reasonable amount of time with a reasonable excuse, they'll probably take care of you within their ability to do so. On the other hand, if you no show a connection because you wanted a day in Madrid, you may be SOL.