Fire works are legal today due to pests. They started with lower class fireworks to scare wood chucks etc. And a simple handful dropped out the window in your back yard is one way to say to the bear your home is not a nice quiet meal, and they will listen. A simple motion sensor will let you know they are back. It would take allot more then them coming in the yard for me to call some bureaucrat who will just put the animal down. The Big no no with black bear is to corner them NEVER Block there exit. 99% of the time if you give them a way out they will leave without any problems. And the Mother bear with the babies she just wants to find food for the kids and keep them safe like any good mom. A first time mom when she has her first child and the relatives come over and someone has the sniffles you can be sure they won't get near the baby. By the time mom is on her third baby and someone wants to see the baby mom is like yeah sure just don't hurt the kid or i'll rip your head off. One theory you never want to try but it explains why some mother bears bring there kids close to people and others are very posturous when they see you close to the cubs.