Stupidity: The "body armor" General Ford and others wear is very bulky and appears to be quite heavy with all the attachments (e.g, flashlights on shoulders). With the protective suit protruding perhaps 8", it would most likely restrict/slow movement, contrary to what soldiers need. Moreover, the body may be protected, but there's no protection for the face/head, leaving them exposed/vulnerable. Today's products tend to be lighter, thinner, and stronger, so would be expected in the future.
Stupidity: Billy and Allie saw there were several men in the area also searching for the medallion and the kids even hid from the men minutes before finding the medallion. Instead of quickly sneaking away after they found the medallion, Billy and Allie stayed in the same spot and Billy shouted, "We found it! We found it!" Seconds later, two men came from behind the tree. (00:24:00 - 00:24:21)
Stupidity: When the marines get the reactor working, Dr Betruger stabs Veronica and kills her so that she will not be able to reveal his secrets to them. However, he stabs her in the lower back, so it would still give her ample time to tell the marines what he is trying to hide whilst she bleeds out. Surely it would have been easier to stab her in the neck or slit her throat.
Stupidity: When the plane begins crashing, Kayla tells Claire that she is sitting in an ejector seat. She also mentions that there are no parachutes because she "wasn't expecting company." If Kayla was expecting to be alone in a crash scenario, what use would installing the ejector seat in one of the passenger seats have been? She would have to move from the pilot seat to the passenger seat while the plan is crashing. Surely it would've been easier to install the ejector seat in the pilot seat.
Stupidity: Even though Hermione reminds them that they must not be seen after freeing Buckbeak, they fly toward the castle, whooping and cheering because they're flying. Then, they land in the courtyard of the castle, have a conversation, and then Sirius flies off with Buckbeak. Not the behavior of trying to remain unseen and unheard.
Stupidity: When the flying snowmobiles attack, Bond tells Elektra to go into the gully, and he'll lead them into the trees...completely ignoring the fact that these bad guys are here to kill her, so why would they follow him instead? Of course they all do. Either a plot contrivance or a blatant set up, which he doesn't remotely consider.
Stupidity: Max loaded his backpack with food and supplies he thought/knew he would need searching for his father in the woods. Before he was out of the backyard, his slightly older sister said she was going, too. Max didn't tell her to get her own food, etc. to bring. Surely he would know that he would have to share his food and run out. Also, when the backpack full of supplies fell into the river, instead of at least trying to see if they could retrieve it, Max just immediately dismissed it as "lost."
Stupidity: The protagonist is wearing normal boots atop a spacesuit while being on a moon mission. (01:37:11)
Stupidity: Stitch wakes up in a kennel with dogs at the animal shelter. When Lilo picks him out and they walk out of the kennel, the lady freaks out and tells Nani, "We thought it was dead, it was hit by a truck!" So, what was thought to be a dead dog was put into a kennel with other living dogs. Think about that for a second.
Stupidity: In a flashback scene, a mother, father and daughter are taking pictures of Norm and two other polar bears. The daughter decides to run up to the three polar bears, but the parents appear to do nothing about it. The polar bears could have been a threat to their daughter for all they knew. (00:04:25)
Stupidity: After making love, Selina notices Batman's scars. She surely was caught in the moment, but, it's something she really was bound to notice sooner. (00:53:10)
Suggested correction: She notices the scars on his back first, which are the worst of those on his body, this may well be the first time she sees his back.
Stupidity: The "keep everyone in the stadium" plan is foiled when gold is scattered around the outside and everyone leaves. The bad guys didn't consider locking the doors? Not least because once the terrifying sky tendrils descend and boiling red clouds start filling the arena, surely people would have started bolting for the wide open exits.
Stupidity: Darren could have easily grabbed Ben out of the locker he climbed into by just pulling. Instead, he pushes it inward, causing it to close and allowing Ben to either hold onto it on the inside or lock the locker itself.
Stupidity: After Noah shoots the Humanity Bureau vehicle following them, they continue down the road and stop at an old abandoned building that still has some sort of running water in it. Lucas has to go to the bathroom so his mother just lets him wander off by himself to find a restroom. She doesn't go with him or make sure he's fine. And this is in an area where they know that most of the residents are hostile, and they are being chased by the Humanity Bureau. Noah even calls her out on the stupidity of her letting Lucas go by himself and she claims it's because he needed to do number 2 and that Lucas insisted and he's not a little kid any more... Which doesn't excuse the stupidity of the action of letting an 11 year old go by himself to find a bathroom in such a situation. And ultimately it does lead to him getting found by Agent Westinghouse. (01:08:30)
Stupidity: There is a map of the area on the wall behind Jason as he tells Sam and Ben to "look for anything useful - maps, food, radios, anything." Also, there is a map in the drawer as Sam opens it, but she removes the notice letter "shuttered for budget cuts" and the snowmobile keys. (00:44:43 - 00:45:20)