A more important question to ask is (and I know I’m going to the lowest circle of gehenim for even suggesting this) — is R. Kanievsky’s teshuva normative halacha? Becuase if you really wanted to, you could always search out the most machmir position on every issue — but we clearly don’t do that. As such, even if R. Kanievsky says it’s assur, that doesn’t make it the final be-all-and-end-all p’sak.
The Wolf