So far Iron Bart, Mia Khalifa1 and Mary420Jane have made a topic about this and I can confirm that at least 2 of those are ironman accounts.
Items dropped in wilderness by ironmen didn't appear at for the player who dropped them, because the items were visible to everyone immediately (whatever sense that made) before it was changed to ironmen cannot drop items at all in wilderness. If the items dropped on death follows the same rules, the items on the ground will disappear for ironmen after only 1 minute, because after that they become visible to everyone. I will test this once I get home.
Tested, works as intended. Died on ironman at rimmington's hero. I watched the items on both my ironman and main accounts and saw the items appear to my main at 1 minute mark and disappear for both at 2 minute mark.
Also confirmed that ironmen cannot see other ironmen's death pile on the ground.