This question was raised in guild chat if we get ruby lvl and so the chest has 25 items what happens when its opened and you only have a bp of under 25 slots ..bound to be loads of players with limited space
Good question hades.
The best solution is after open the chest the items will go to the mail box and wait there for 24 hours.
If the player have less space then he will figure out what the most needed items and took from the mail box.
And since the items will stay 24 hours, so he has enough time to figure out how to take those. He would either get rid of unneeded items or put some items in the AH and make some space.