3. CR and ECL introduce the era of "balanced encounters.".
I disagree. I think that this is a mistake by people not reading the full section of the DMG on Encounters. If you read the 3.0 DMG (can't state whether of not this is true of 3.5), it gives two types of encounters: tailored and Status quo
Tailored: You take into account the party"s abilities and that of the opposition
Status Quo: Things exist in the world without concern for the PCs level. The player's have to adapt to them. They know the 20 HD big bad Dragon exists in the swamp even when the PCs are first level. It is their decision to go after it or avoid it. (note: The actual example was the bugbears known to exist in a specific location regardless of the party's level).
The DMG tells the DM that they should warn players if they are *only* going to use status quo encounters (emphasis on only is mine).
I don't see the above much different than previous editions with wandering encounters in the wilderness or placing monsters at specific locations at the beginning of the campaign and adventures for party of level x. They just give you more explicit guidelines rather than leaving it entirely up to the DM or designer to figure it out entirely on their own..
Granted, there is a section of the DMG that goes further into discussing tailoring adventures, because the designers don't know your group or the exact party composition. However, it does not eliminate that option of status quo encounters and, since you are only supposed to warn the players if you wil not be using any tailored encounters, I think it is fair to say you are assumed to be using a mix of both.
Furthermore, when designing encounters for an adventure, the DMG gives a break down of various difficulties. 5% are recommended to be Ovewhelming which is ECL 5+ higher than the party. The DM is then told that the party needs to run or they will most likely lose. There is nothing balanced about this.