I go in with the assumption that people didn't lie but just messed up. And that's especially possible in such a "chaotic" raid (pretty deserving of this description tbh). But my assumption is wrong of course, I just want to imagine that everyone is honest.

With more spaced out, orderly, less chaotic fights like Extreme or Savage, it's rather more obvious they are lying. But I don't think all of them view it as lying. Many of them:
  • Didn't read the description.
  • Interpreted "be up to p3" as "have seen up to p3 but usually with deaths, vulns, bleeds and damage downs".
  • Interpreted "be up to p3" as "having seen p3 one time".
  • Maybe got through earlier phases consistently because they had someone carrying them hard ie. a healer spamming shields, or a tank 100% managing the aggro for a co-tank with provoke/shirk/shared mit and adjusting for them because they don't know what provoke/shirk/mit is (I've had to do this for people before).
I see people who join when they aren't ready as just not very considerate.