Continuity mistake: When Wayne is on top of the giant bunny holding the bullhorn he is in front of the bunny's hair in the close-ups, but hidden behind it in the angles where the baby holds the toy (though the bullhorn is still visible), obviously to hide the miniature-Wayne trick.
Continuity mistake: The chocolate stain on the baby's face when home behind the net changes from dark to light between shots.
Continuity mistake: Nick and Wayne walk towards the giant baby for the first time, next to where a clock is. In the wide shot following, they're two metres behind, walking towards that same spot.
Continuity mistake: In Las Vegas Adam slides the car and sparks come out. His brother is either holding the wheel or waving his arms, depending on the shot.
Continuity mistake: Adam picks up the yellow car sideways but the shot inside shows Nick and Mandy upside down.
Continuity mistake: When Adam is blown up, he gets chocolate all over his cheeks. Then he has a nap, but when he wakes up, all the chocolate is gone.
Continuity mistake: After he eats the entire box of fudge bars, Adam has chocolate smeared all over his face. The smudges change shape and intensity several times between takes. (00:39:00)
Answer: She may have said goodbye to Adam but it just wasn't shown.