Agreed, but orders from the top did not always translate into good behavior by every soldier, especially when lower grade officers were willing to look the other way.
Allen Guelzo's recent book on Gettysburg discusses this question at some length.
The reality was, as reported by Confederates themselves, that once across the Potomac into Pennsylvania, troops were allowed to do pretty much what they wanted, with or without formal "requisitions".
You mentioned Early's 1864 burning of Chambersburg, PA, but that was only the last of three Confederate raids on Chambersburg, the second being Lee / Ewell's Corps in 1863, which Guelzo describes as quickly descending from huge "requisitions" to confiscations, to robbery & looting to finally simple vandalism (see chapter 5).
You know, I've long argued that in the greater scheme of things, especially when compared to other armies at other times in other wars, our ancestors on both sides were better behaved than any you can name.
For just one example, my estimate is that the number of civilians who died directly from the Civil War was in the neighborhood of one for every thousand soldiers killed.
Compare that with WWII where two civilians died for every soldier killed -- no comparison.
But there were some atrocities, looting and destruction, on both sides, neither remarkably more or less than the other, when opportunity and need were present.
Lee is a great hero but there are some things he did not tolerate and pillaging was one of them and punishments were severe. He also used file closers which was very controversial at the time. The way I understand it one of the duties of file closers was to stop pillaging. However once Lee started to use file closers the Union quickly followed suite.
Like I said the Army of the Potomac did little foraging ( the Shenandoah valley excepted) because it was the best equipped and supplied Army in the world. Logistics was its forte. The other Union Armies - not so much and we don't even need to discuss Sherman's' bummers.