I agree. You shouldn't draw a line until you've pushed your abilities to the max.
I don't think you have the right to interfere with the universe like that
Are we "limiting ourselves" with this kind of thinking? perhaps... but are limits really so bad? Do you really want an anarchic universe where beings simply step in and do things without permission? Or do you want to live in the universe that runs on the system was planned out by it's omnipotent creator, and set up with infinite balance between perfect chaos and perfect order?
This is an interesting topic to me, especially since I've been doing studying on Psi. Since I see very little distinction between magick and other approaches to channeling Psi energy/potential/etc
One might argue that we have the "right" to do it just be being able to do it. A lion has the right to claw out a zebra's intestine, why should we be so arrogant as to hold ourselves above natural laws?