Ah my bad. Commenter you're replying to is saying we never should have built this capability, and it's a terrible idea (my own words now) to weaken boundaries to this degree, it can never be done "safely".
But it does exist, and your own request to opt in is reasonable and would mark an improvement.
spoiler
My initial hasty comment:
What? No, it shouldn't exist. Either I'm trippin or you missed the point of the comment you're responding to.
"Opt-in" (your preference) can only exist if the capability exists. Comment says it shouldn't. Commenter is correct.
What is it you are saying...?