Sure, UPnP can open ports to the outside world, but that's something that might be desired in some cases.
However, devices should default to local access only, and offer an option to expose them to the world, with appropriate warning.
However, devices should default to local access only, and offer an option to expose them to the world, with appropriate warning.
Unfortunately we need to act based on what is and not what should be.
Ofcourse for most people who aren't dealing with state secrets convenience is a priority.