I expect their efforts to pass such hardfork to fail, but who knows if like I said, most people in the future depend on ETFs and start pushing for laws to "protect investors" that force developers and miners to do rollback plans and so on. This sounds ridiculous now but you never know.
I'm not sure how anyone could write laws that force bitcoin developers/miners to do rollback plans or anything else. The jurisdictional nightmare of trying to force compliance would make the point moot. I'm pretty sure if a any city/state/country tried, Argentina and maybe other countries would come out with a law that made it illegal to comply...