Many of those "accidents" are not really accidents: I've seen two kinds of ways sites engineer those "accidents"

(1) many sites, like phys.org, have crowded and confusing layouts that try to trick you on clicking on an "x" or something to close an ad but really clicking on the ad, there's a lot of deniability on this on mobile where the touch accuracy is poor

(2) a few years back there were a lot of sites which seemed to always change the layout when you were trying to click on something in the sidebar, anandtech was one of the worst, i could swear they were watching the mouse events and predicting the click events. this stopped all of a sudden, could be Google put the smack-down on this behavior