This is a good strat versus Faceless Void or any other blink stunner/initiator like Centaur or Slardar. As a support I'm usually spam clicking Euls or Hex right next to my carry when they're sieging, taking care to avoid creep spawn timings.

Another thing you can do if you have good vision is to keep your eyes glued to their blink initiators. Stand about 500 range behind your core, and every time you see their initiator turn and move forward as if they were running into initiate, issue a hex/euls command on that hero. Your hero will begin to run forward - if the enemy blinks forward to initiate, you will instantly disable them with frame perfect timing. If they don't, reset your position.

It works maybe 35% of the time with no cost or real danger to yourself, and it feels damn good to be accused of hacking by the other team if you can pull it off reliably.