Do items stack if used by different teammates? If so, should they?
To give an example, let's say that both the support and the top laner buy Frozen heart for teamfights. Do the effects of that stack?
Harder example: Darius and Lucian both but BC and start auto attacking the enemy a Maokai. Is Maokai taking the armor shred of one black Cleaver or both? If he is taking both, should this be allowed when considering how much lethality and %armor pen are getting stacked to kill both squishies and not squishies?
Simplified: Do status effects from different sources stack on top of each other?