Sorry if this has been posted already.

I think it would be useful at Luminaire time if there was a notice when the gift you're about to give is already under the recipients tree.

This has been suggested in the past. The old thread shouldn't be necroed, but I believe the arguments made in the thread still apply.

blocking duplicats under tree?

As I wrote in the old thread, I think this suggestion, while it does have some upsides, creates larger problems than it solves.

• Once you're slipping a gift under the tree, you've already spend sP/CSC on an item, so you end up with a useless item and having to spend more resources to buy another gift.
• It can be abused to spoil gift surprises.
• A lot of people do actually want duplicates of items, besides obvious things like currencies, boosters and stuff they hoard, even single use items like clothing can be desired for both wardrobe and TC.

There are many ways to deal with the original problem of getting duplicate items you have no use for. You can sell them to get sP, you can use them as trade fodder to get items still on your WL, or re-gift them. Finally, one of my friends this year set up a gift exchange thread which was a really creative way of dealing with the issue.