For that exact same reason I've been avoiding half-sized up/down keys and full arrow keys, as well as mate screen and weight, have been my first filters when browsing for laptops. How annoying must it be to design those machines with such a variety of tastes :)

I feel the opposite -- with half-size up/down keys, it's too easy to mis-press them. I guess it's a matter of habit.

I am not sure I understand this argument. With all other parameters being equal, I would assume that the larger the button is, the easier it is to mis-press that button. Half-as-large buttons should be harder (twice-as-hard) to mis-press.