JPH wrote:

Can you give an example of how an airspace violation could occur? It
seems that as long as the pilot doesn't descend below the minimum
altitude published for the segment of the approach he's in, then
descending on the glidepath can't put the aircraft any lower than
dropping down immediately to the minimum segment altitude at the
beginning of the segment. If he's in the Intermediate, then the
glidepath will more than likely keep him higher than dropping down to
the minimum altitude due to the length of the intermediate normally
compensating for the required altitude loss at 150 ft per mile optimum.
If the airspace violation would be from the aircraft being too high,
then perhaps the procedure should have a maximum altitude shown or the
controller issue a crossing restriction.

It's happen at LAX quite a few times when the air is hot and the
underlying Ontario airspace rises to provide less than 1,000 feet of
vertical on the LAX G/Ses. The G/S doesn't move.

The glideslope intercept altitude is a minimum altitude, not a mandatory
or maximum altitude. From a TERPS standpoint there's no problem with
descending on the glideslope from 2000 on the procedure in question
instead of 1800.

True enough, and if the pilot wants to remain above the G/S that is
perfectly legal. But, any charted minimum stepdown altitudes prior to
the PFAF are governing, not the G/S.

If the pilot uses the glideslope for backup vertical guidance to give a
smooth transition to the final segment (while using the altimeter
readout outside the FAF to ensure he doesn't descend below 1800) then
what's wrong with that?

Nothing wrong with that.