“how hard would it be to notch two bollards just a bit then bottle-jack them apart enough to wiggle through?”
It has not been a problem. The bollards are hard, thick steel. They have been the solution to the problem of people cutting holes through the other metal fence designs.
Hardened steel. Okay this can work, but I wonder about the cost and servicability. Once you harden steel it’s not so workable and weldable as before amirite?