Flying over the runway is illegal?

Recently, Jose posted:

Despite the two rulings, pilots should realize that currently there
is nothing in the FARs to warn you that conducting a "low approach"
will only be deemed appropriate if the airport or runway is one upon
which your aircraft can land.

I wonder how one can legally practice engine-out procedures (trim for
best glide, find a suitable field...) since part of the practice is to
see if one can actually =make= the field one has picked out by using
the procedures one is practicing.

Well, I don't need to be below 500' agl to know whether I've made the
field, and I don't practice engine outs at 600'. ;-)

Neil