Christians do not believe that. We believe she DID go to His tomb at first light!
It says so RIGHT IN THE BIBLE.
But Catholics cannot admit that. That's why they run away when you pose the question.
You know, at first I thought Polycarp was a bit over the top taking people to task over belief in the genuineness of the ossuary (which for the record, I'd like to find out it is genuine, but either way it doesn't improve or detract from my faith). Then berned came along and things got really crazy.
I am a Catholic. I've never been anything else. And in 30+ years of Catholicism, I've never had one priest, nun, family member, or fellow parishioner state to me that they believe anything but that Mary was there for the whole thing.
I don't know which Catholic church services you've been auditing, but you ain't been in any of the dozen or so churches I've belonged to over the years.