https://www.joelonsoftware.com/2000/04/12/choices/
Particularly relevant here is the part about the user who made their taskbar take up half the screen, making their computer unusable.
> Every time you provide an option, you’re asking the user to make a decision.
The best-of-both-worlds is when you give users an option, and then you pick a sensible default for it. Some of the best options are the ones that 90% of people don't even know about, but the 10% that do can find when they need it. I can't tell you how many hidden "defaults" commands I have run that are not even exposed to the UI but make my life much, much nicer.
It has really the wrong focus. It talks about pop-ups and distracting messages; it talks about surprising interfaces; it talks about actions that are hard to undo. But it doesn't talk about any problem that options cause by themselves.
Who is "we"? That didn't describe me in 2000 and describes me even less today.
Being able to moving the taskbar is bad because his friend shot herself in the foot this one time, but "we all love Winamp skins" -- because the person whose winamp turned unusable because they double clicked the wrong file just didn't happen to be friends with Joel. Sure, don't make software for me, but don't try to rationalize it with such gymnastics.
I wonder why they even bother letting it go to half-screen?
People who just randomly click things without even realizing they're clicking may just as well delete random files or worse, the taskbar taking up half the screen is about the most harmless consequence I can think of. If it's really such a worry, add a dialog that asks the user "are you sure you want this?" for anything "weird", with a checkbox to "never ask again". If people "accidentally" click that, too, that is really their problem.