Hi
good point but you will be able to unlock the device using the traditional methods too, but you could use the tap code when you consider that its better no taking the risk of somebody watch your screen.
From an attacker's perspective, taking into account that people are generally worse with reusing pins than passwords, why would this make a difference in how hard it is to compromise a device. Also, how many combinations will this provide?
Good answer. Could be interesting then. I use double tab to signal i want to use my phone but still need to solve a riddle. So this would fit my workflow