  A simple analysis of time-dependent $B_s\to K^+K^-$ transitions, based on
recent results from the LHCb experiment, is presented. The benefits of adopting
a fully consistent theoretical description of the $B^0_s$--$\bar B^0_s$ mixing
are stressed. It is shown that bounds on CPT violation in the $B^0_s$--$\bar
B^0_s$ system can be consistently obtained and that direct CP violation in
$B_s\to K^+K^-$ can be robustly established, even in the presence of CPT
violation in the mixing.
