There was a time when electronic tuners didn't exist (for anyone here young enough to have missed the days of checking a dial tone in whatever city one found oneself and then using an A-440 tuning fork to figure out what note was sounding on the dial tone. Then, if one lost the tuning fork ya could always get tuned appropriately. Of course, tuning by ear is ideal, and I don't care to see tuners on guitars, but then that's just a matter of taste and aesthetics. I play often with musicians who keep tuners attached and that's fine with me. What I find to be a danger is strings that haven't been clipped or wound so they don't poke holes in one's skin. About that there oughta be a law. YMMV.