I've voted to deprecate based on my understanding that either passing a non-empty string or relying on the default value would trigger a deprecation. It wouldn't make sense for me to only deprecate passing an explicit argument.
I agree that the path forward has not been made clear in the RFC. Will the escape parameter be dropped in PHP 9? Will only the default value change? So if there's a debate about what the RFC actually meant, I wouldn't mind postponing this change.
