I am very, very big on simple Quality Of Life things for players. If the players defeated someone or something, and there's something there they might wish to investigate, I would not ever put them in a situation where they HAVE to intimately seek out every pixel-bitchy detail in order to reap the spoils of their labor. I wouldn't mollycoddle them, it's possible for them to make a mistake and such, but I would *at the very least*:
-- Ask, "Is there anything you would like to do with his/her/its body or items?" This doesn't tell them there's anything fancy--but it does ensure they're
aware of the fact that the body has items, even if they're all mundane.
-- Run a passive check for anyone who spent at least a couple rounds near the opponent during the fight. If any passive checks succeed, I'd tell that person (openly, for the whole group) that they sense something there. Not specifically what or where, but enough of a hint to invite additional investigation.
-- Let them know, after/between sessions, that there ARE things to be found, if you go looking. My current 4e DM did this shortly after we started. We had thought that the cargo on a ship we'd boarded was destroyed in the fight (plasma cannon to the deck can do that), so we hadn't bothered to check for loot--our mistake. We've been careful to examine bodies, items, and locations in future efforts, though that too has occasionally bitten us in the butt.
-- If someone in the party has been, in-character, expressing a need or desire for certain things (new spell scrolls, perhaps, or a shiny new weapon, or a shield, or the like), I might give a gentle reminder through descriptive text. Stuff like, "The orc warlord lies dead; any soldiers loyal to him that you haven't captured or killed have fled. It is odd, seeing the cause of such suffering and strive crumpled on the ground, bleeding onto his shield and axe, still and growing cold." Or, "Your fireball, square to the face, burns off the wizard's facial hair. He's thrown back by the force...and doesn't get up again. His wide-brimmed hat slowly falls to the ground, unscathed, and a few things fall out of his burnt robe."