I think making macro_rules! respect hygiene with respect to unsafety is a reasonable change for an upcoming edition (or at the very least macro macros, "macros 2.0").
(And I argued against the plutonium advisory, in favor of the safe! macro (which is just aliased unsafe).)
Given that it's purely safe code to rm -rf / --no-preserve-root, though, I don't think "finding potentially malicious code with rg unsafe" is a good argument for it.