Yes, it is highly doubtful that the action of typing would be likely to change one's opinion in and of itself.
For starters, the modification isn't permanent. In fact, iFixit is already selling a kit with a screwdriver that is a close (but not quite perfect) match with the new screws, and a set of the original type screws to replace them with.
Apple is relying on security by obscurity, but this is short-lived. The screws are industry standard, it's just a standard so new that for the time buying, the screwdrivers are hard to come by.
And yes, it's legal.
In all fairness, neither is your iPhone.
You're welcome to that opinion. However, you kinda already know this going into the situation. If you open up your iPhone, new screws or not, your warranty is voided. It's another in a long list of products, some made by Apple, but many not, that share a common warning: "No user-serviceable parts inside."
Fortunately for you, there's Android. And plenty of other vendors who I'm sure are equally unhappy about the idea of users taking apart their phones.
It's evident you're not a lawyer. The challenge you seek is unlikely because chances are, someone challenging this will lose, and waste a lot of money in the process.
You mean like how cars that aren't welded shut require regular maintenance?
Unlikely that Apple would ever do this. On the scale of consumer electronics, anything that requires periodic service is more trouble than it's worth, both for the potential user and the vendor.
We Trust