Things can and most likely will change with the new FAA re-authorization. However until the FAA works out its new regulations, it is still operating under the same rules as before. Under Part 336, we needed to operate under rules/suggestions provided by community-based flying organizations. Typically the AMA is the organization everyone goes by, and the one also mentioned by the FAA.
On the FAA Drone Zone site, they specifically list the altitude restriction of 400 feet. Look here --->
Recreational Fliers & Modeler Community-Based Organizations
Step 2: Review the rules states:
- Fly at or below 400 feet when in uncontrolled airspace (Class G)
So neither the FAA nor the AMA list this 400 foot rule above structures. However it has been widely accepted as the norm. Since we are still flying under Section 336 and since it is allowed for Part 107 pilots, then it seems that recreational pilots also can. Yes I know it's not written in stone and if you want to be totally safe then just stay under 400 feet period.
I know there may be disagreement and this is my view. I think we can all agree however that the intent is to keep everyone safe. All tall structures are clearly marked on sectional charts. All manned aircraft pilots should be reading these charts and never fly lower than 500 feet above such structures. If you don't agree with my interpretation, I respect that and I understand that it can be interpreted that Section 336 pilots can never fly above 400 feet.