If time travel cannot affect our own history, and every trip back branches a new reality, and those new realities have no effect on our own, then as a practical matter, from our point of view, there are no consequences for intruding into this new reality. Yes, anything one of our clients did would affect them, but that was a them problem, and also, from a philosophical point of view, anything that happened in that reality was meant to happen in that reality, otherwise it would not have happened, or could not have happened.
