Make no mistake, almost any random company does not wish to afford you any more "rights" than necessary. When they sell a product to you, they want you to - without a doubt, wholeheartedly - believe you cannot do with it what you wish. This is partially false.
CDs, DVDs, video tapes and beyond are physical copies of data spawned from an original source of some sort. It is true you do not own the material on the medium, but you do own the medium. It is true you cannot reproduce a copy for non-personal usage, but you can for personal usage (network storage, general backup, or a copy to take on the road or to let another individual borrow). It should always go without saying one may copy without restriction a piece of software they've purchased.
Where it gets tricky is hardware (not a physical copy such as a DVD) and software combined. Reasons why one should be allowed to exercise First Sale law are simple (and sometimes complex, but we'll stick to simple ones for now).
A few years ago someone had stolen my PlayStation - Full set - 4 controllers, games (I don't recall how many, but enough to keep you busy), HDMI and multiple USB cords for charging purposes. This came at the worst time for me (not that any time is great to have things stolen from you), so it was unpleasant. A few times I had actually thought about selling the set for money, but knowing me I would've never followed through.
Skipping forward, I bought another PlayStation and a few of the same games. However, my progress on one of my most loved games (Gran Turismo) was forever lost. I tried every route to regain it, but no luck whatsoever. Rightfully so, I started my journey in figuring out how to "hack" the game to make my progress back. I didn't have any intentions on playing online anymore as the next version of the game had already released, and most of the lobby was dead anyway, but I did want to play offline.
Considering I had purchased a DLC (Downloadable Content) pack which enabled access to several more premium items in the game, some would believe you can still have said premium items. However, this is generally not how games work. You still have to complete the initial progress which lead to being able to even purchase the DLC pack. So, not only had I purchased the game twice (by this point) and purchased additional content, by not being able to load the saved game from the previous PlayStation my progress (in game), the requirements were not met, disallowing me access to the DLC completely. Sad moment when you realize you can't race your favorite Audi R10 TDI with the hours of adjusted specs.
Initially, I thought I will attempt to regain the progress through natural play, but quickly became bored of that as I was only completing things I had already did, over and over, and sometimes hours to do due to the tediousness of the challenges, or the fact that one can't sit on a console all day without chores (adult life) taking higher priority.
I started to research how I could edit the progress of the game and to my surprise, it was easier than ever as the game had been around for a few years.
I did the thing, 1, 2, 3, done.
Had millions in cash, top level and guess what?--Finally access to my purchased (by USD) vehicles! You can only imagine how ecstatic I was, being able to simply "enjoy" the content I once obtained through vigorous challenge.
Simply put, just because I had edited my progress back does not mean I should've taken advantage of that via online sessions, because I did in fact boost myself higher than I should've by giving myself more than enough money (in-game money) to purchase the vehicles, which meant I could obtain any vehicle in-game that I desired.
This is kinda evil only if I played online, because there are clearly other people that did not make their way to the top via a game modification.
Where we draw the line between offline and online play after such modification is quite simple:
By all means, play offline all you want with a modified game. There's nothing wrong with this. But don't make changes to the system and game expecting to take advantage of other players or the service itself. This is not the idea behind modifying systems. However, I remember back in the mutually accepted days of game hacks, there were public "mod" servers you could play on and no one would bat an eye. Counter Strike, FEAR, Halo (1) and more.
Simple, same concept applies. The overall "online" portion of the service can't be cheated.
Maybe I have engraved free and open source philosophical viewpoints about how software and hardware should be handled or governed, but I do know F/OSS has never hindered anyone from progressing.
Have a good day!
HACK THE PLANET!