I differ with all posters here. The rule is, and I paraphrase, something that was designed to prevent access by bears. The key word is designed. As long as you stay in the Inyo National Forest, you can use a 6 oz. Ursack. It is certainly designed to prevent access by bears. If you search the Inyo website you will find the exact wording.
Secondly, if you are going to be camping at Trail Camp, bears are not the issue, marmots are. All you need to do is hang the Ursack from a rock above the ground.
My friends and I have been using Ursacks for over 10 years without a problem. In that time we have seen the ubiquitous Bear Vault fail on several occasions.
