Originally Posted by TTRotary

Unfortunately, this is not a guideline anymore. As certification holder, you have certified that you will not fly over 400AGL under any circumstances. There is a statement at the bottom that it is a felony to misrepresent any aspect of your registration. That's the teeth.

I will also point out that early language stated a 400ft guideline irrespective of proximity to an airport. Somewhere along the way, the comma got dropped and it became 400feet within 5 miles of an airport. It is clear from the registration that the FAA always intended for the 400 foot rule to apply unconditionally. And it is not a suggestion. Ignore, or pretend it is a polite suggestion at your own peril.