If you have 2 or 3 monitors and a program like EVE-O Preview v3.1.0 “Lykoi” (multi-client preview / switcher) (perfectly legal) you can lock and fire as fast as you can move the mouse. Fitting 6-8 in a single server tick really isn’t that difficult.
If CCP hasn’t banned them, it’s because they haven’t caught them doing anything illegal.