The reasoning behind the real lights situation.

The situation and result:

There are 5 players, lights were off, and you somehow get an emergency meeting called and someone says "Somebody was messing with the lights panel!" What does this mean?

For one thing, it's likely the case that there are still 2 impostors if lights are being messed with and that you aren't sure that the person you voted off was an impostor. Who are at lights and who is at button? Under optimal strategic play by everyone, 3 people are at lights (including one impostor messing with the lights panel) and 2 at the button (including one impostor guarding it and trying to get the final kill). Once you made it to the emergency meeting, you can safely vote out the person who was at the button room but didn't call the meeting because that's an impostor.

The reasoning behind this:

Why then, assuming nobody is cleared, is this the best play from impostors on both sides? Well here are some reasons:

• It's necessary that one impostor is on the lights panel messing with them in order to buy time for the other impostor's kill cool down if and only if impostors want to play to win on this round.
• It's necessary that one impostor is guarding the button in order to prevent an emergency meeting to get called and to get the final kill or fight to press the button first before a crewmate if and only if impostors want to play to win on this round.
• It's better for there to be 2 crewmates going to lights along with the impostor instead of just one because 2 can beat 1 at the lights panel and get the lights turned on faster.
• That leaves the last person, which is a crewmate, to also camp the button in order to try and get the meeting called off first and vote out an impostor.

So what's implied by someone saying that "lights were messed with" while under the condition that both impostors were trying to win by getting a kill on this round, crew can safely vote out the impostor who is at button and clear the person who called the meeting.

If it's not the case that it's possible for there to be an impostor at the button as there are 2 people, then this is either the situation of the fake lights play where the only impostor is trying to get a crewmate voted off or that one of the impostors wasn't playing the situation right for getting a kill win.

Other factors:

If you include a small amount of time for crewmates to plan out what to do and you have a cleared crewmate, the arrangement of this situation can change significantly. The cleared crewmate could camp button, in which both impostors would go to lights this time in order to avoid suspicion, or go help fix lights, in which you have the same arrangement as though nobody was cleared.

If there are 2 crewmates that are cleared, impostors would be grouped together along with the crewmate that is not cleared, or there is one impostor in that situation going for the fake lights play.

If there are 3 crewmates that are cleared, crewmates just win with safe shots regardless if there is one or 2 impostors alive still going for real lights or fake lights.

Final conclusions:

The only real implication that could be made from "Somebody messing with lights" is that there is at least one impostor messing with them in that area. You can make this conclusion regardless of whether you're in the fake lights play by one impostor or the real lights play by 2 impostors. The first thing you need to distinguish is that if this is the real or fake lights play, then you figure out how many people are cleared, what exactly happened, and then you go one with the implications from there.