It's still better to attack with advantage even if you have a -2 cover penalty.
If a fighter is in melee and the halfling is hiding behind it, I would say that halfling is in danger! With the way OAs work now, a monster could just walk around the fighter to where he thinks the halfling is, see him, and attack.
Depending on the situation, getting advantage might still be worth it. And the halfling can break up his movement, so he can hide, fire, then move away to relative safety.
The rules don't support that interpretation, however. In order to hide, you need to be unseen and unheard, there is no restriction about a creature knowing where you areMy interpretation is that the benefit from hiding is predicated on the fact that the creature doesn't know you're there. If it does, it seems like you shouldn't get the benefit of hiding.
Absolutely it can. However, 1) the hiding creature may not appear when the attacking creature thinks it will. 2) if it does appear in that spot, guess, what, the hiding creature isn't hidden anymore, as it didn't stay out of sight.I can even imagine a scenario in which the creature anticipates the actions of a character who tries to hide while under direct observation. That creature could then take action in response based on what it knows, rather than what it sees. For example, it could aim an attack at the location it believe the character will emerge from.
Fair enough. My statement about the situation being moot was not well thought out.
I do want to point out that any creature can get cover from other creatures, not just lightfoot halflings.
Lightfoot halfings can hide behind large creatures, which is what I think you meant.
BR60 Hiding: In combat, most creatures stay alert for signs of danger all around, so if you come out of hiding and approach a creature, it usually sees you. However, under certain circumstances, the Dungeon Master might allow you to stay hidden as you approach a creature that is distracted, allowing you to gain advantage on an attack before you are seen.
Lightfoot Halflings can attempt to hide behind creatures one size larger than them ("Naturally Stealthy" pg. 17), so yes, I think they can keep doing this every turn.
Attack, Cunning action to hide behind the fighter.