: I think the reason ONI declared them dead is because they more needed to hide
: the Chief's defection from the Infinity's crew, not the spartans but the
: normal everyday guys who work in like engineering and stuff. The needed a
: way to explain why Blue Team was absent from the Infinity.

They could've just said they're on a classified mission. If they'd been AWOL for weeks, I could see them considering it, but they were away for just a couple of days or so. It makes the whole fanfare about Chief turning traitor or this big epic manhunt kind of goofy when you consider how soon he ended up coming back.