This suggestion expands upon "Request a SimPlayer to come to you for a trade", suggested in January.
I came across an issue where I had an item that Arty was asking for. I whispered "come here" to him and he said "no thanks". I asked where he was and he was one zone over. Looked for him in that zone to no avail, then I asked him where he was and he zoned again. By the time I found him and traded the item, he no longer wanted it.
Having an override chat message like "I have your item" which lets SimPlayers know why I am asking for them to "come here" would greatly improve field trades.