Theoretically, your plan is perfect, but in practice you need to factor in human error.

Wikileaks is a good example. The website is set up in a way that makes it impossible to trace whistleblowers using technical means. But as we have seen, if they brag about their whisleblowing to the wrong friend then they can be tracked down in meatspace.

Nothing will protect your store against old fashioned forensic analysis of the packaging you use for your parcels, for instance.