My idea is that a company should be allowed to claim any numerical value they want for "privacy" or "security" in advertising, but, if the "privacy" or "security" is breached they should be required to pay out the number claimed to the entity who breached it. In the case of mass consumer products, they should probably also be required to specify a per-unit value.
This scheme has many advantages. First, it prevents companies from overstating too much since if they claim a number much more than the cost to find a breach, then it becomes profitable for white-hats to demonstrate that (e.g. they say $1 Billion, but it only costs $1 Million). In fact, if they really overstate it they will be appropriately "fined" for their false advertising. This means that the number will probably be similar to or less than the true cost.
Second, it allows companies and users to choose their risk. If a user has uniquely valuable data or a specific use case with greater requirements, they can choose a service with the level they deem appropriate. If a company manages unimportant data or is too new to have high "security", they can specify a low number to properly reflect the value of data they can or will protect. This avoids the problem of a single fixed value that could prevent low "security"/importance systems from being created and could shield high "security"/importance systems from the liability they should have to manage.