Continuity mistake: When Adam is throwing things at his brother, a shot from the outside of the house shows the blinds totally closed, but they appear slightly open from the inside. It's not until 10 minutes later that the father shuts them.
Continuity mistake: When the four police cars are riding together along Las Vegas street, the rear shot shows then beginning at the 4 Queens hotel but the immediate front angle places them many meters away.
Continuity mistake: In Las Vegas, when the ice-cream truck is about to play the music, the position of the baby's feet, the lettering on the billboards and the people next to him change completely between shots.
Continuity mistake: When Adam is toying with the car in Las Vegas, the wide shot shows the girl's arms extended, but in the close-up they're covering her face. This swaps back and forth.
Continuity mistake: When Wayne is in the back of the van with his machine when the motorcycle cops are following him, the switches on the machine change position depending on the shot. At first, you see #2 and 5 in the up position, but then only #4 is. He flips them all up and the lights come on, but in the next shot, the lights are off and not all the switches are up. A similar thing happens when he unshrinks the cops.
Revealing mistake: After Adam passes the car by the palm tree, when he slides it and makes sparks, Nick's hands are not real but from an obvious miniature.
Revealing mistake: When Adam falls face-front in Vegas one can notice that Nick and Mandy have been replaced with two stiff toys.
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.
Revealing mistake: After the giant baby grabs the giant bunny he then grabs his dad's head and the baby is replaced by an obvious inflatable doll.
Continuity mistake: The chocolate stain on the baby's face when home behind the net changes from dark to light between shots.
Audio problem: In Las Vegas, before the yellow car scene Nick says "we have to jump", but his mouth isn't moving.
Revealing mistake: When Mandy is hanging loose by the car's edge and Nick is grabbing her, there's a shot with a bluescreened background where Nick says "but you gotta help" where Mandy and the car are all blurry and faded and the image is doubled. Something went really wrong in that special effects shot.
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.