For those interested, I have a guide which covers surprise and other topics of discussion in this thread:
http://www.enworld.org/forum/showth...Stealth-Hiding-and-You!&p=6702270#post6702270
As for me, I've always run surprise as ending after your first turn in initiative, the confirmation from JC is nice to have though. And yet, there's people in this thread who argue it doesn't work as described. I don't get it.
As for the initiating surprise bit, I've always followed that whatever prompted surprise (attack, movement, speaking, etc..) was always resolved first. Then, I would look at who didn't notice the threat whatever prompted surprised posed and apply surprise accordingly and finally roll initiative. Whoever doesn't notice a threat, even if plainly visible, is surprised in 5e. It could be the man standing next to you in a crowded market place suddenly stabbing you in the back, the rogue hidden in the darkness of the alley shooting an arrow at you, etc.. Being hidden/rolling stealth is NOT a requirement to initiate surprise! Some of you seem to be under the impression that the only way to cause surprise is to be hidden via rolling stealth vs perception and then attacking or something. It's simply a question of noticing a threat or not which is DM fiat for the monsters and resolved by passive insight / passive perception. These are specifically for this sort of situation! That's what the DM rolls against with his thug as he approaches your character in the marketplace. The DM can even rule that your character is distracted by the wares he's looking at and doesn't even have a CHANCE to notice the thug. I mean it's all there in the rules guys and gals.
I decided to resolve the triggering event, whatever it was, before assigning surprise and rolling initiative for a couple of reasons. 1. It makes most of the arguments presented in this thread moot. 2. It allows the assassin rogue to actually benefit from his archtype feature. 3. It's still completely dependent on the DM allowing for a situation where surprise is even possible in the first place. 4. If done this way, even if the assassin (if there's even one in your game) manages to get surprise (because you allowed it in the first place) makes an attack to initiate surprise (requiring an attack roll which can miss) and crits because of his feature (if he's of the appropriate level) and then rolls initiative and wins (another die roll he can't control) and finally gets ANOTHER attack which might crit if he hits: WHAT DOES IT EVEN MATTER? The enemies are there to be defeated, if you allowed surprise in the first place and then everything went well for the assassin in the group why do you even care about your monsters? The assassin is happy he got to crit via his feature, the party is happy because the assassin just kicked some butt, the group plan for how to start the encounter worked.. I mean literally everyone at the table is happy and excited! So why does it matter? Many of the people who tell me this is wrong don't seem to grasp that the objections they are making are irrelevant at the table. Who cares if my monster gets 1HKO by the assassin. The point is to have FUN and I made a houserule that I use because it simplifies everything and I don't run into any of the problems listed in this thread.
GL HF.