Ok, the example with Red Team is really bad. The only reason there wasn't more of a military presence there was because of Red Team. And even then, that cutscene isn't entirely accurate to the lore. Yes, MJOLNIR is a powerful combat system. But without energy shields, that armor is about as effective as that of Stormtroopers in Star Wars, at least when pitted against Covenant weaponry. Case in point, Samuel's armor was catastrophically compromised from a single shot from either a Plasma Pistol or Plasma Rifle. With that information in mind, Red Team was insanely lucky that the Sangheili that attacked them didn't have ranged weapons with them. But beyond even that, the Sangheili appeared to have forgotten that their armor had shielding and neglected to turn it on. The amount of conveniences there have convinced me that canon was sacrificed in favor of an admittedly awesome action scene. Spartans are powerful, but the odds of any of the three members of Red Team surviving combat against an entire legion of lance-wielding Sangheili in full combat armor are slim to none.