I only vacuumed SG tins that I was not sure where they vacuumed anymore. All was not opened before but couple of them I was able to open without any force so I thought that the seal was broken.
Pretty sure plastic covered vacuumed sealed tins will rust, this has been mentioned lots before, but lots don’t know. Anyhow my tins in a humidor rusted after something like 3-5 years. Open air is best for sealed tins. Vacuumed pouches would work though