After re-reading everything, I think I may have discovered what you were thinking: I suspect you wanted to pick up the gas dropped by P11 as opposed to doing a trade. Generally, items dropped by other players can NOT be picked up by others. This game made an exception for when a player is killed and drops their items. However, P11 was not killed, so the item(s) dropped by a player by choice are not available to other players. Sorry about the confusion.