It took Harry several days to get used to his strange new freedom. Never before had he been able to get up whenever he wanted or eat whatever he fancied. He could even go wherever he pleased, so long as it was in Diagon Alley [...] (4.1.1)
Harry sort of lives out everyone's childhood dream here – what would it be like to have no adult supervision? It's fitting that this novel starts out with Harry living out a child's fantasy since, for the rest of it, Harry has to do a lot of growing up, which is a largely unpleasant business. As we'll see, growing up can involve a lot of restrictions on that very freedom.
He accompanied them to the entrance hall, where Filch, the caretaker, was standing inside the front doors, checking off names against a long list, peering suspiciously into every face, and making sure that no one was sneaking out who shouldn't be going. (8.4.5)
The image here of Harry having to stay behind with Filch, who acts like a jail warden, is really powerful. Hogwarts has become a sort of prison for Harry.
"The fortress is set on a tiny island, way out to sea, but they don't need walls and water to keep the prisoners in, not when they're all trapped inside their own heads, incapable of a single cheerful thought. Most of them go mad within weeks." (10.2.39)
Azkaban is really the ultimate prison since it traps people within their own minds, the worst kind of entrapment, really. However, you don't have to be in Azkaban to experience that kind of entrapment. Take Snape, for instance, who's so consumed with rage over the past that he's basically trapped by it. What other characters are trapped in their own heads or by their own emotions?
"I certainly believe his master's defeat unhinged him for a while. The murder of Pettigrew and all those Muggles was the action of a cornered and desperate man – cruel [...] pointless." (10.3.177)
It's fascinating to revisit passages like this after learning the truth about Pettigrew (yeah, this book calls for a re-read). Peter is such a coward that you'd expect him to just beg for mercy when he's cornered. But he has a vicious streak as well as Houdini-like escape abilities, which make for a dangerous combination. Turns out the massacre that Black supposedly did whilst "unhinged" is even scarier than anyone realizes; it was actually the calculated act of a cruel and selfish man.
"Where's Buckbeak, Hagrid?" said Hermione hesitantly.
"I – I took him outside," said Hagrid, spilling milk all over the table as he filled up the jug. "He's tethered in me pumpkin patch. Thought he oughta see the trees an' – an' smell fresh air – before –." (16.2.9-10)
Hagrid basically equates freedom with nature here, which is interesting given how often freedom and flying are linked together in this book.
"Harry!" said a voice in his right ear. Harry started and looked around at Hermione, who was sitting at the table right behind them and clearing a space in the wall of books that had been hiding her. (14.1.49)
We love how meaningful the details are here. First, we have Harry hearing Hermione's voice in his right ear, like one of those mini angels perched on his soldier, trying to drown out the voice of the mini devil on the other shoulder. This hints that Hermione might just be more than Captain Logic – she also functions as a sort of conscience for Harry, trying to get him to do the responsible and "right" thing. Second, the image of Hermione clearing a hole in her wall of books is perfect – it demonstrates how she's literally built up walls and trapped herself with her own overachiever tendencies.
"I don't know how I did it," he said slowly. "I think the only reason I never lost my mind is that I knew I was innocent. That wasn't a happy thought, so the Dementors couldn't suck it out of me [...] but it kept me sane and knowing who I am [...] (19.124)
Sirius finds a sort of freedom in his own efforts to remain sane. It seems like freedom boiled down to keeping a hold of his sense of self, which is probably still true outside of Azkaban.
"I must admit Peter, I have difficulty in understanding why an innocent man would want to spend twelve years as a rat," said Lupin evenly. (19.104)
Again, we see another kind of imprisonment, and another example of imprisonment by choice. Also, kudos to Lupin for being this book's breakout comedic star.
"Well, in that case, Potter, you'll understand why I don't think it's a good idea for you to be practicing Quidditch in the evenings. Out on the field with only your team members, it's very exposed, Potter –." (9.2.8)
Harry is frequently confined to the school or closely monitored during this book.
Neither Ron nor Hermione felt like going, however, so they and Harry wandered onto the grounds, still talking about the extraordinary events of the previous night and wondering where Sirius and Buckbeak were now. (22.2.1)
We find it really fitting and awesome that Harry and his friends choose to stay behind on the last Hogsmeade trip of the year. Harry spent the entire novel trying to go to Hogsmeade, and in the end it seems that the freedom Hogsmeade represented rather paled in comparison with the type of freedom he was able to give Sirius. There's even a sort of freedom in being with good friends that Harry discovers here; he doesn't need to go on a field trip to have that.