Robustness: Our experimental results suggest a fairly robust
system with paired-user accuracies in excess of 96%. However,
we caution that a controlled lab study is not a good
proxy for real-world use. Our experimental results should
be viewed as evidence that the underlying technique is valid
and may be a tenable way forward for supporting instrumentation-
free, identity-enabled, mobile touchscreen interaction
– the first technique to achieve this end. This opens
up the possibility of future work, which we discuss next.