In the past 20 years, I've lived across the major metro areas of Seattle, Silicon Valley, and now Los Angeles. in all places, it's been common practice for delivery companies to leave packages outside unless the shipper has specified otherwise for a high-value or theft-prone item.

Over literally thousands of deliveries during that time, the number that have disappeared mysteriously is under 1%. In fact, more have not been delivered at all (i.e., fraud on the part of the delivery person) than have been stolen.