We have recently been made aware of an unintended use of game mechanics that is being used to kill tethered ships by flagging them with a PVP timer using an ECM Burst.
From the date and time of this message, using an ECM Burst to PVP flag a ship that is tethered to a citadel for the purposes of giving additional time to bump it out of tether range for destruction is considered an exploit, and will be dealt with as such.
This issue will be fixed with the 118.7 release on Tuesday, August 9th, 2016, however in the meantime it will remain an exploit to use the combination of ECM Bursts, bumping and the PVP timer in this manner.