The wishlist is nothing more than a convenience to the user and does not trigger an automatic dibs on the trading day. You will be able to view your wishlist and call dibs from it, but that would be a manual action on your part.
DogsNDaylilies said:what happens if multiple people request the same items?
If there are 5 offers for a plant, the first five to call dibs on it get it. This would happen starting after midnight UTC on the opening day of trading. If you really, really want something, you should make sure to be present as the clock turns and call dibs on it right away.
If multiple people call dibs at the same time, it's first come, first served. If there's only one offer available and two people click at the same time to get it, the first one who clicked and confirmed (Even if by a single millisecond) gets it. The second (slower) person will get a message saying "Sorry, there are no more offers available for this plant."