Mistwell
Crusty Old Meatwad
Realistically if the party wasn't doing silence 10' radius in every room they engage in combat, its really likely that the rest of the dungeon is going to know they are there.
I disagree. In my own house, which is no mansion, I could scream at the top of my lungs and my wife can't hear me from the other side of the house.
And it's just a normal wood lath/plaster home.
If you're in the room next door, you'd hear. Otherwise, probably not. I do roll checks, but the odds of hearing are not favorable as you get further away behind more doors and walls.
So the logical thing for them to do would be to set up ambushes and try to come at the party in force.
When they are aware, this is exactly what they do. Indeed, many modules set this up just like that - and in the one I am reading right now, that's precisely how it works.
That's realistically what would happen. However that is not how most dungeons are set up. Most of them are set up with each room separate and the monsters unaware they are being invaded.
I don't know what "most" you're speaking for, but I disagree. Certainly TSR dungeons didn't usually operate that way, and this most recent 5e one doesn't operate that way, and I know some 3e ones didn't work that way.
Try it sometime. Set up a protocol and some perception (listen) checks for nearby rooms and then have them all gank the party when they engage in combat. See how fast that lasts before you have a few dead party members. It will likely turn into an epic battle where just as the party finishes off one group the next 2-3 groups have made it in to reinforce.
Not only do I do just that, but I even SAID I did just that, and it's one reason you and I are talking about this topic. You responded to me saying I did that, remember?
(The DC for a listen check in 4E is 0. You add 1 per square distant to the sound. So most checks in that dungeon were around 15-17 which monsters of the level made easily due to +1/2 level added to their ability mod.)
Not sure it matters what the DC was in 4e.