FAA regs. for minimum altitudes over built-up areas

Forgive me for not being aware of this, but I fly up in Canada, and in
our CARs (602.14 and 602.15), Canadian regs. very specifically prohibit
the operation of a fixedwing A/C over a built up area at less than 1000
feet above the highest obstacle within 2000 feet horizontally of the
A/C. The exception to this rule is if the A/C is conducting a
take-off, an approach, or landing.

As I have noticed in the discussion of the unforunate death of Cory
Lidle, the East River VFR corridor is about 2000 feet wide in many
places, yet fixed wing A/C are regularly flown there at altitudes as
low as 400 feet AGL, with many buildings along the shore-line up to
several hundred feet tall.

Considering that the ideal flight paths of A/C up and down this VFR
corridor are within a few hundred feet of the shoreline, this type of
flying would not be permitted in Canada.

In fact when I think about it, I spent a few weeks in Boca Raton,
Florida not too long ago and noticed that A/C are regularly flying up
and down the shore-line, well within 2000 ft horizontally of built up
areas and condos 200 - 300 feet tall, at altitudes as low as 300 feet
AGL. I know there's an airport nearby, but most of these planes were
not taking of, landing, or flying any kind of published approach. They
were, like most traffic in those NYC VFR corridors, sight-seeing.

I live, and got my training in (and above) Toronto, and this type of
low level flying isn't permitted, and rarely seen.

We have a very vocal anti-airport interest group here, and if this kind
of flying were permitted over Toronto, our downtown airport would be
under even more pressure than it aleady is to be shut down. I cannot
imagine what the reaction would be if if a private A/C actually crashed
into a building in the downtown area.

What's the FAA regs. on the matter? Is there some exception in place
for New York's VFR corridors (or Florida's beaches?)

PPL-A (Canada)