A fullgrown boa easily has the strength to kill an adult if it hits the right spot, which is why you don't go walking around with 7' snakes wrapped around your necks. People aren't natural prey items for these snakes, however mistakes can be made, or nobody would ever receive anything other than defense bites. All human fatalities that have resulted from large boids constricting them have been from pure stupidity when handling them. If there is a child in the house, make sure that the cage can be locked with a key, not just a bolt-type lock or turn key (and especially not an aquarium). There is no reason for that snake to escape a properly built, custom enclosure, but it also needs to be kiddy-proofed as well, just in case that kid doesn't listen to what he's been told
It's all just common sense to keep the situation safe