An accidental “Bad Tick” shouldn’t be a problem as long as your broker or a Liquidity Provider correct the false numbers later on and restore positions executed by the event.

The problem would be when the “Bad Tick” is caused intentionally in order to make a profit on broker’s(or LP’s) side. In this case, these companies wouldn’t correct any false numbers as it could lead to a great loss for themselves.

Unfortunately, it is very difficult to distinguish a “Bad Tick” was an accidental one or an intentional one.

What traders can do would be, reporting the issue to a regulatory authority which your broker is under. You may contact a specific authority which can investigate the matter.