How would we know if you just went to the second last boss with a shield and just discarded it before?
I supposed you just have to trust me! And there's no incentive for me to do that, my bag is filled with gems and energy items. There's no room for shields and even if i have a space for shield, the amt of block provided is not worth it. I rather have energy items to let me deal more damage. Also the shield will reduce my energy from 4 to 3 because of berserker ring's effect.