It gives away the fact that you are deception in rated warzones, that is enough for most teams to call focus fire on mumble/vent/ts...hence you will be kos and shut down. If you use thrash instead, it is not as apparent but still against good teams they will notice. If you are running 0/27/14, the thrash just reduce the cost of shock, which means you could just pop it without 2x thrash if you have the force. Deathfield at 30 range is much better for stopping caps and dmg anyways.
When I see voltaic slash x2 from a sin, i force shroud right away and 3/4 of the time I see a few resist messages pop up. Works like a charm. Or just chain cc on you to prevent your burst or delay it as long as possible, reducing your effectiveness. Assassins, if not in tank spec, works best if you are not being noticed, VS is a dead giveaway unfortunately due to how flashy and rare the animation is. He prob meant shut down as in the sense that your effectiveness is severely compromised.
Seems like you fight some really bad ception sins. And i don't die that easly.