@ jeremyr, in a traditional western music setting, wind and string instruments have different tunings, but are all still based on A 440, similar to those of us who tune our basses flat, but are definitely still on A 440. there are examples in certain areas of western music history where different tuning scales are used, (equal temperament [the most common], mean tone, pythagorean, to name a few), especially with keyboard instruments such as harpsichords, but generally speaking, if it was a "band" situation (lol), the tunings would match up.
what does that have to do with perfect pitch? i disagree with gouche's sentiment, because centuries ago, people played several instruments of several tunings without problem. i dont mean to insult him because he's definitely due alot of credit and honor for his skill on the instrument, but his inability to play as proficiently on basses of other tunings has almost nothing to do with his perfect pitch. i say that because i dont have perfect pitch and when i started playing bass 3 yrs ago, i played ADGCF, then in the second year i decided to go standard. it was the hardest thing i ever had to do, because i LEARNED playing the bass with the A tuning, and i too (without perfect pitch) was unable to play cuz i wanted to hear Eb on the first fret of the d string. eventually i got it. and when i switched to flat tuning it was hard, but not AS hard. now i can play any of the three tunings, not NEARLY as proficiently as if i was playin flat cuz that's what im most accustomed to, but the point im trying to make is its just a matter of training your brain.
my dad has perfect pitch, and one day we had a competition to see who could get notes faster. this was when i was unsure if i had perfect pitch or not. of course i lost, and i realized i didnt have it. he's a doctorate of musical arts in piano performance, so he's taught alot of students over the past 40 years and he told me he encourages people to develop their relative pitch, but he has NEVER seen a student develop perfect pitch. cuz perfect pitch is a reaction not a thought process. i hear Ab and i KNOW it's Ab, but i do have that split second of thinking. my boy has perfect pitch and he doesnt have to think about it, when he hears notes or chords, he sees colors! anyways, my point after all of this talking is, IMO you can't learn perfect pitch.
as far as it's worth in a band situation, my boy that has perfect pitch is a keyboardist and we always used to play at stuff in school. if the p&w leader started a song, he would always start up instantly in the right key. i mean i play keys too, and its not that i cant hear the key that the person is singing in, but there's sometimes a bit of a delay. not w/ him, and that may be a small advantage, but one nonetheless. another advantage is up here in MA/CT we do alot of lines, and in rehearsal teaching them can be kinda difficult sometimes, but he is always real quick w/ it, cuz he can SEE the lines as opposed to relying on relative pitch. and im not saying that you can't be fast with relative pitch, he's just FASTER...
sorry for the essay lol, just my two cents