[joab]

I agree
You have no idea what the dogs true intentions were.
Shooting would have been irresponsible and doing nothing could have been painful.

As for the old lady and the poodle
They make pepper sprays in all sizes and they will sell them to just about anyone.
You can't be around to protect everyone that doesn't see the necessity to protect themselves.

I might try to inform the owner that his fence is malfunctioning though, it is entirely possible that he does not know