edit: i think there are certain situations heads up when you might get more by not tossing in that extra bet prefop with aces, multi way this is never the case.
That's the key, really. A lot of people advocate just calling a 3-bet when we are HU with AA. In that spot, I prefer capping mainly because I cap with lots of hands in that spot (in shorthanded play, anyways), but multiway, this should never be an option.
It's the same as us flopping a set, and betting out and getting raised, if we're HU, we can conceal a bit, but if I get a coldcaller or two, I'm 3-betting all day.