I think that the very idea that phone manufacturers are going to the lengths to engineer phones that are IPx8 rated indicates how much of a problem phone wetting is perceived to be in the market.
Sitting in a NYC bar last weekend, I had a full glass of water knocked over right onto my Note 7 (and, no, not to extinguish it, smartasses). If that had been my S6e, it'd be a question if that would have been a problem, and with my S4, it DEFINITELY would have been an issue (ask me how I know). But, since it was the Most Beautiful Phone I Ever Owned, I just wiped it down with the same bar rag that the bartender was using to mop the bar, and it was fine.
Remember, much like driving, it often doesn't matter how careful YOU are with the phone. How careful are your fellow humans, and Mother Nature?
-Mark