Yes American outlets are already more dangerous than European style; when the switch plates are missing there are exposed live contacts on the sides.
I don't know why but it stood out to me how many houses (of friends) I saw where all the switchplates were gone. At some point maybe they're removed for painting/wallpaper, or they just break, and either through a lack of money or lack of motivation never get replaced.
Traditional outlets have the plates held on by just one screw. That screw runs through a piece of plastic that is just 0.4 inches (10 mm) wide. The screw pulls the whole plate against the wall, which probably sticks out a bit due to an uneven surface. That stress point, right at the screw, will break.
I don't know why but it stood out to me how many houses (of friends) I saw where all the switchplates were gone. At some point maybe they're removed for painting/wallpaper, or they just break, and either through a lack of money or lack of motivation never get replaced.