[quote name='ZilchWoolham' timestamp='1505408914' post='3371734']
I have to assume it's because the band all tuned to each other and not to, say, a tuning fork. It makes sense that this practice was more common before the days of cheap digital tuners.
[/quote]
Yes. Back in the day (ahem) there was always a piano somewhere at the venue and we'd all tune to that. Obviously the chances of it being at concert pitch were slim, in fact, they were rarely in tune with themselves. At that time it was considered acceptable to come on stage, spend five minutes tuning up, mumbling and otherwise faffing about before starting the first number. No slick stage routine or any of that. Yes, I know.