Stupidity: John, the guy who taught Chucky the voodoo spell is confronted by Chucky later on in doll form. When things don't go how Chucky wants, he finds a Voodoo doll of the same guy just lying around and uses it to torture him. So this idiot who knows Voodoo and what it does, happens to have a Voodoo doll of himself just lying around? Yeah sure, that can't go wrong at all.
Suggested correction: Not all magic is evil, and the doll could've been made for something else.
Stupidity: Hans keeps a major part of his plan secret from his own team: that the electromagnetic lock will be disabled if the FBI shuts down power to the building. The mercenaries hired as muscle don't need to know the minutiae of the plan, but it seems ludicrous that Theo wasn't told. Theo states on more than one occasion that he can't proceed past a certain point and that he hopes Hans has a plan for the final lock. Evidently, Hans was keeping this information secret simply to amuse himself, which makes little sense considering how much planning went into the heist.
Suggested correction: Or because he simply doesn't trust anyone with that kind of knowledge. He neither trusts them or cares about them, it's all him.
So he trusts that Theo would be on board with all the murder and mayhem, open all the other locks, be in a tactical lookout position when the police try to breach, and drive the getaway vehicle. But he doesn't trust Theo enough to tell him the last lock will open when the power goes out?
It's not about trust; Hans needs Theo to do what he is there for and that is all you mention up to the final lock. He has a plan for the final lock and so there's no need to discuss it with the team, since it won't be any of them responsible.
The more people that know the plan the more chances of someone talking. Especially when they are hired mercenaries.
Theo was already on board with taking hostages and committing murder. Him knowing that the power needed to be shut off to open the last lock doesn't appear to be particularly important information you would need to keep from someone to keep them from talking.
If he's the only one that knows the final step to get the money, then at least up until that moment he is absolutely indispensable to the plan and ensures no-one would double-cross him. In any case I'm not sure being more cautious than necessary really qualifies as "stupidity."
Stupidity: Jack has been using Mosley's badge and identification to pass himself off as FBI. He never once uses this trick to commandeer a civilian car for him and John when it would have been the safest way to get to L.A. much sooner.
Suggested correction: Probably because If he did that, the car's owner like Red the bar owner would eventually call the FBI office to get their car back and then the feds would know the make, model, license plate, and the last location of Walsh and the Duke. The police would have caught them in minutes. Walsh had to keep a low profile.
Stupidity: Amongst the dubious statistics attributed to the real Frank Dux at the end of the film is the claim that he holds the record for "Most Consecutive Knockouts in a Single Tournament - 56." A single tournament with at least 56 rounds would include over 72,000,000,000,000,000 entrants.
Suggested correction: While the entire film could be considered fiction based on Dux's dubious claims, your statement is only valid for a single-elimination style tournament. There are other types of tournaments, such as a round robin which would only require 57 contestant (Dux plus at least 56 guys to knock out).
The kumite is a single elimination tournament. It wouldn't make any sense to have a full-contact tournament, where the action is so (legally) violent that fights routinely end in severe injury or even death, use any other form of bracket.
Nothing is stated that every tournament Dux was in was the Kumite as depicted in the film. Just that he retired undefeated in the Kumite.
The records listed at the end of the film are kumite records. The information comes from Frank Dux himself who made the claims on more than one occasion. When it says 56 consecutive knockouts, it is referring to the kumite and not some other, possibly round robin (which honestly would still be a ridiculous claim) tournament. It is likely the makers of the film believed "consecutive knockouts" meant "single tournament."
I guess everything I've read on him over the decades never made it clear it was talking about one type of tournament with all the accomplishments he's claimed to have. And I've read the same repeated factoid about how many contestants 56 rounds would have that you read.
Stupidity: When Jonathan is chasing the truck to try and save Sarah, he could have removed his heavy backpack and run faster...but instead just leaves it on. No wonder he wasn't fast enough.