Mixed emotions on the warning. Like it, so I wouldn't forget and leave them on, going down the road. I'd be removing it the day after using it to do something in back of the truck.
On the rockers, I do a lot of unique, custom woodwork. My entire interior (dash, glove box cover, ashtray cover, stereo frame, overhead console (gauges), dash, lower door panels and so on were all wood. First pine, to get the feel (it actually looked kick butt), then mahogany.
To pull that off, I had to mount all the gauges, including the stock speedometer and fuel gauge in the new dash, doing away with the circuit board. Not being overly foolish, I had high beam and turn indicators (I used 24 volt lights, so they would have lasted a bazillion years).
Switches for some of the equipment, including replacing an inoperative heater switch, included lighted rockers. They, well, ROCKED. Way ROCKED.
IF you don't mind slightly dimmer bulbs, put a few ohms in front of [or after] the switch bulbs, if they allow it, to add years to their life.
SIDE NOTE: The reason the Edison bulb is yet burning in a fire station is, it's being run at a lower voltage than it is designed to run at (over a 100 years going, now).
In the end, adding the ability to turn the backups on when the rig is not in reverse is far easier than we might be indicating.