Completely safe in my opinion. I would never keep metal in my house unless I had intentions of getting rid of it.
Here ya go: http://forums.silverstackers.com/topic-43574-behold-ss-ignore-user-feature.html knock yourself out
Set up a trust, then open the (safety box) account in the name of the trust. Probably the safest option. The old adage, "own nothing, control everything."
An old news story, but another risk to consider in regards to the safety of safe deposit boxes: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10829698
Most roller door security access is monitored with cams. If this bloke followed the car in he should be on Candid Camera'. Did they get him? OC