This is a good topic, and underscores the 'catch-22' we find ourselves in when the rulebook meets reality.
Working hot ... you tend to think of foot-thick cables carrying a gazillion volts. Yet, the little bitty wires on a ballast can make you just as dead. Indeed, 277v is just about at the 'gee, I can't let go' threshold. If you do manage to let go, your next worry is what to do when your keester hits the floor
Naturally, the easiest thing would be to simply flip the light switch. Enter the bean-counter and the control-freak manager. Rather than have every room switched, they want it all controlled by a single switch down in the basement. Sure, let's put the whole building in the dark every time we replace a bulb! Plus, we've now introduced all the hazards of working in the dark. Flashlights? Try hiking through the woods at night sometime, if you think a flashlight is equal to daylight. Not to mention the uproar as all production ceases while the lights are out.
So someone has the bright idea of wearing PPE. This leads to the temptation that 'more is better.' Before you know it, you're climbing the ladder in 40lbs of special clothes, and wearing gloves almost as thick as the tires on your car. No wonder the 'troops' hate PPE.
What about a disconnect in the fixture? There's an idea. Am I the only one who remembers the time when most fluorescent troffers had fuses and starters? Care to guess what usually broke? Well, the little 'disconnects' they now mandate might be a good thing ... except that I've yet to see any two alike, or replacement ballasts come equipped with them. This means that every ballast replacement leads to -again- replacing the disconnect fitting. You're still "working hot." Or, you have a belly pan cluttered with a rats' nest of pigtails and wire nuts. Pick your code violation- cable fill or hot work, your choice.
Cable fill concerns are not trivial. Those blessed little wires are already trying their best to get pinched when you replace the belly pan; I'm sure we've all popped a breaker when we cut into one as we put it all together again. Oops.
The kicker is ... this is all caused by the lack of that light switch, and the lack of good lighting design. Ironically, the 'energy codes' are mandating both of those in their roundabout way.
How about we just get out of the way, and let the pros do their jobs?