Today, Naked Security reports that it gets much worse: "Tapplock's cloud-based administration tools were as vulnerable as the lock, as Greek security researcher Vangelis Stykas found out very rapidly." From the report: Stykas found that once you'd logged into one Tapplock account, you were effectively authenticated to access anyone else's Tapplock account, as long as you knew their account ID. You could easily sniff out account IDs because Tapplock was too lazy to use HTTPS (secure web connections) for connections back to home base -- but you didn't really need to bother, because account IDs were apparently just incremental IDs anyway, like house numbers on most streets. As a result, Stykas could not only add himself as an authorized user to anyone else's lock, but also read out personal information from that person's account, including the last location (if known) where the Tapplock was opened.
Incredibly, Tapplock's back-end system would not only let him open other people's locks using the official app, but also tell him where to find the locks he could now open! Of course, this gave him an unlocking speed advantage over Pen Test Partners -- by using the official app Stykas needed just 0.8 seconds to open a lock, instead of the sluggish two seconds needed by the lock-cracking app.