First let me say that I highly doubt that anyone would leave their party members so far away not for demonstration or exploit purposes. But I would like to see some comments from other players on the matter. Maybe someones playing style is all about scattering the party around the map.
They dont need to be so far ...
That happened just bcs Swen wanted to show us that he will deal with Hag solo with his druid ...
When i approached Hag, i had all my party prepared just there in that gate, stealthing ... then they sneak inside and attacked her one by one.
Bcs its effective as hell, Hag had almost half HP gone before her first move.
Im not quite sure if that is conciderable as exploit,
personaly i see more exploits in that you can lock her in chat ... and while she is waiting for your talking character to choose his reaction, you can sneak behind her, and showe her down.
You know? I watched the video, I know what and why happened. And that's irrelevant. I'm not talking here about the most clever ways to kill the Hag, I'm talking about the system involved in Swen's attempt, which he praised a bit in the video (I gave the link), and how so far for me and one another person that system was more a source of frustration, than a helpful thing.
2. There are a few enemies, who can be approached in stealth from different angles, and that's exactly what I'm doing. My first character to engage gets his initiative roll appropriately. After that I need to switch to each one of the rest of my characters to get them engaged, they are now considered to be late for the fight and forced to skip their first turn. That doesn't feel even partially fair, they were right there and prepared for the fight. Why are they late for the fight?
I believe i know answer for this one ...
If you sneak them to battle properly, you are able to attack from real time - world ... that is your first attack you are skiping otherwise ... pretty powerful tho since all your characters are attacking at same time and NPC have no way to defend themselves against it (except AC and saving throws ofc.).
And if you dont, well that is your price to pay, when you decided to try to use this approach ... not sure, but i take it as they are simply surprised. :-/
No, you don't know the answer, because you didn't understand the question and should read how "surprise" works.
Player characters, who's looking right at their enemies from stealth, cannot be surprised, and they are not surprised. They just start living at different time pace the moment one character attacks and even if NPCs are surprised player characters will be forced to skip the first turn, because again the game considers them as ones, who joined the fight later. They can attack from their stealth, ofc, like in your example with the Hag, but then they won't have their opportunity to fully utilise all their points (action, bonus action...). They attack, they are getting flagged as "ones, who joined the fight", as well as "ones, who are slightly late for the fight" and will be allowed to act more only on the next turn. You technically get the same exact situation if you leave the party around a corner and start the fight with just one character. If you'll bring the rest of your party, they'll start with skipping one turn. That's more or less fair, they really wasn't there when the fight started. In the case 2 I described in OP post I'm talking about player characters, who are sometimes nearly breathing in a neck of an engaged NPC, but they'll still skip the turn, because we can't tell the game that all of our characters are going to engage and should join the turn-based mode simultaneously.
