A client-server system and a blockchain method for calculating whether a time-crucial shipment is located according to an expectation comprising a client device adapted for being adhered to or placed within a time-crucial package shipment; and a remote special purpose computer server comprising a transit plan schedule database based on pickup time and location stored in memory, the remote special purpose computer server being programmed to calculate a location of the client device based on data accessed from a Wi-Fi access point location database, the transmitted identification data, and the transmitted signal strength data, and compare the calculated location to an expected location based on common carrier schedule transit plan pickup time and delivery location received from third party database sources.