Any kind of warning that would be useful would be tough to implement. The ones that cars use for backup hazards and blind-spot monitoring are very broad. There is something somewhere behind you so be careful, or there is a vehicle in the other lane so be careful. They don't inform you of how many inches or even feet are between you and the hazard.
I think the best those types of automotive systems could do would be to constantly warn you that there is a rock ahead or a tree ahead with no useful info on whether or not your pannier will actually clear it. You would probably also receive a mind-numbing amount of mostly useless warnings. Rock ahead, rock ahead, tree ahead, tree ahead, rock, rock, tree, tree, rock. People would just disable it
The cost of implementing a system that would tell you if your panniers were hanging too low to clear rock or if an opening was too narrow for them to squeeze through a couple of trees, would make those panniers crazy expensive. I can't imagine that there would be units sold to justify the design.
I have seen that video above a few times and I really don't know what he was doing. Not paying attention obviously. But that is also a sport-tourer where the panniers stick out significantly further than the bars.
Adventure bikes have much wider bars so a bit more of a visual guide upfront. They are a bit like a cat's whiskers. If the whiskers are a close fit, don't follow that up with trying to fit your fat cat butt through there. It is likely not going to end well
