Stupidity: Leia was carrying a handheld bomb. Yet she doesn't think to bring it with her later on while freeing Han.
Suggested correction: Novels from the Expanded Universe make it clear that with the exception of guards, nobody is allowed to carry weaponry in Jabba's Palace.
Stupidity: When trapped in the net, Luke asks Han if he can reach his lightsaber. Han says that he can, but turns out he can't. Luke has the force. Why doesn't he just use it to make the lightsaber fly into his hand instead of having Han reach for it in vain?
Suggested correction: The way they were stuck in the net, Luke's hands weren't free for him to force reach, he would not have been able to grab the lightsaber had he used the force.
Jedi don't need their hands in order to Force-reach. Most of them just choose to do it, as a way of focusing. Luke later lifts C-3PO in front of the Ewoks (to make them think the droid is a god), even though he is tied to a stick.
True, but read the whole comment, Luke's hands weren't free to grab the saber so a force reach would have been pointless.
Suggested correction: They were in it for mere seconds before R2 cut the rope, and they fell. Luke just didn't have time to think of forcepulling it.
Then it makes it a stupidity if Luke doesn't think to use the force.
In those few seconds they were in the trap? Hardly.
If Luke had enough time to ask Hans if he could grab his lightsaber, then yes.
Close enough.
Stupidity: When Luke jumps onto the second skiff the skiff pilot is at the other end and has plenty of time to drive away to remove the threat of Luke and save all of his friends and Jabba, but instead just stands there with no reaction. It's like its an empty costume, there is also a skiff guard in white at the front that is nearest Luke, but again no reaction. In the next shot he is seen going over the front.