I should add that while I've never been charged, I have crashed. It was a motorcycle, about 15 years ago when I was even dumber than I am now (a feat in and of itself, lol).
I never spoke to the officers after the event, likely because I was unconscious in a trauma unit. But I KNOW I could have been charged. The nurses and doctors all visibly winced at my odor and I was lectured, as I deserved to be. There are two possibilities: The cops simply didn't feel like bothering, or they presumed that the very serious injuries combined with a totaled bike and a previously clean record may have been deterrent enough.
On discharge I instantly went shopping for another bike, apparently because I am insane. A scant few months later I was in a diner having a drunken grease pit of a meal at 4am or so. I noticed the adjacent table sneaking looks in my direction. Eventually, one of them asked, "Dude, didn't you just total a motorcycle on so-and-so street?
"Erm, yeah. Wow, that sucked. You were there?"
"Yeah, the sound of twisted metal woke us up. And yet here you are, drunk, with another bike parked out front? Are you $#@! ********?"
I took this heart and was so humiliated that I never rode a bike drunk, again. Good thing, too. Like kids who perform mine-sweeping duty, drunk riding is an activity that carries an extremely short lifespan! So while I urge everyone not to drink and drive, I'd like to take this opportunity to especially stress it to you motorcyclists.