I had to order a new handlebar to replace the one that was damaged in a crash last month. The bar arrived yesterday, along with a second box that included a set of tires. I did not order, nor did I pay for, the tires. I sent an email to the company's customer service department about it to let them know. I'm happy to attach a shipping label and drop it off next time I'm near a UPS/FedEx outlet.
Of course, if they don't get back to me, I'm probably not going to chase them down.