I know with XABF, one of his inhaler medications always required him to rinse with mouthwash, to reduce the chance of the "extra dry mouth / very sore throat" side effect that came with it.
He'd always use the mouthwash with alcohol, simply because it was cheaper. (His mother picked it out and bought it for him.)
I could always tell for sure when he'd had way too much to drink the night before, though, because he'd literally gag on the mouthwash, and have a really hard time gargling with it after using his inhaler. He'd gag on his whiskey in the mornings afterwards, too, although somehow he had a bigger reaction to the mouthwash. So yes, I'd imagine it can really pack a punch, if someone is desperate enough to go that route.
XABF wasn't at the point where he'd drink the mouthwash. (Still, after rehab, I replaced his alcoholic mouthwash, his mother hid her extracts, and his sister gave his giant collection of cologne to her son. I suspect he's angriest about the cologne, since prior to this he never left the house without wearing some.) He also never touched my bottles of extract, or the cooking wine. He stuck to his cheap whiskey, so I suppose in the scheme of things, he hadn't progressed as far as many.
He progressed way too far for my tastes, though. Part of how he earned that "X".