[c1yd3i]

How would you implement this? Are you talking about amending § 91.119?

See: https://www.law.cornell.edu/cfr/text/14/91.119

You'd also need to amend right of way rules:

See: https://www.law.cornell.edu/cfr/text/14/91.113

This would make it very hard for anyone operating smaller aircraft under busy charlie or bravo shelves. Also, would there be exclusions around airports for pattern work?

How would folks operating the toys even know about these altitudes? Really, if the toy can enter echo airspace, it should require some sort of license to operate.