You should be allowed to trade promo cards.

I understand why 2 star cards and above aren't allowed to be traded but event cards should be allowed, my friend wasn't able to get the onix from the Venusaur event even after doing every combat during the event, I went to trade it with him and found out I couldn't even tho I have 6, I feel like we should be allowed to trade those so you can complete your collection even if you have terrible rng.