It is already here. Not humanoid (yet, but it's in the works) but tracked robots with bolted on machine guns have both held and captured positions in UA.
To be honest, I'd be fine with a lot of stuff here but the problem is that mainstream robots are heavy and I fear them falling on my children. Children are unpredictable to machines but most parents find that their behaviour is anticipatable. The sample rate on our sensors and the inference rate in our intelligence is just orders of magnitude beyond the state of the art robots. I am just far more sophisticated and capable right now. My hope is that a sufficiently lightweight device is possible here though I can't see how given the weight requirements of batteries.