The segregation of bands is a very sensible idea, putting good manners on a legal basis that is simple to use.
A park flyer is unlikely to have its transmitter upset anybody else. More likely, it will be affected by the other guy. When it hits something expensive belonging to a neighbour, guess who gets the bill? The unknown crystal thing is a very good reason for the adoption of 2G4.
If you decide to flout safety rules out of sight in private where you 100% cannot affect anybody else, that is your concern. When you set a bad example in public, a different story altogether.
As wonderful and safe as you think you are and indeed might be, when somebody less wonderful than yourself sees you and does the same in the wrong circumstances, a problem that affects the rest of the hobby arises. Monkey see, monkey do. It only takes one irresponsible individual living it up for a few seconds to cause the rest of us years to live it down. And living down the unwarranted reputation will invariably involve higher insurance premiums.