airwalkrr said:That is a presumption of 3e I believe, one that I have grown to have some level of distaste for.
As others have noted, this isn't a presumption of 3e. It is a presumption of people who have not fully read or remembered the rulebook.
I don't have my book on me to give you page references, and the information isn't found in the SRD, but if you look at the DMG section on designing encounters, you will find a table that gives suggestions on how powerful encounters ought to be. It says, quite clearly, that at least 5% of encounters ought to be of the "Turn and run or the party will all die" variety. Yet another 5%, if I recall correctly, are supposed to be of the "Some of the party might survive, but taking on this challenge is still stupid" variety.
So, something like 10% of encounters are expected to produce PC deaths. That the rules call for everything to be beatable is a myth.