The event is not included in any demo nor the current version of Baldi's Basics Plus.
The Test's blindness effect could be similar to the Lights-Off event.
In the Baldi's Basics Plus early access trailer, a more finalized version of the lights out event can be seen due to the inclusion of the new lighting system.
It was possible that this event would be added to update V0.2, but the Gravity Chaos event was added rather. Instead, it might be included in a future update.
It is possible that due to the similarity to The Test's blinding ability that this event will not be implemented, but this seems to be unlikely.
mystman12 confirmed that Lights-Off is going to be reworked. Probably it is not going to be an event.
↑"Some examples include all the lights going out or Baldi breaking his ruler so he can't be heard. There's even a party event where an awesome item will spawn in a room." - Kickstarter page description
↑Baldi's Basics Plus Early Access Trailer [OFFICIALLY OFFICIAL] - 0:25
↑"That idea has been reworked into something else that isn't in the game yet!" - Micah McGonigal, Gmail