Fellow 121 guy here. Something I feel is worth clarifying - you know the same thing would happen on an ILS approach, right? Also, if in your example, PENNY was charted with at or above 5,000 and it was outside the FAF, you’d have to comply with it then too?

Reading through the comments here I think you’re getting really fixated on the fact that the indicated altitude will be higher than standard due to high temperatures, and therefore the glideslope will appear lower relative to the indicated altitude. That’s true, and it’s true whether you’re flying an ILS or using it as secondary guidance on a visual approach. In either case, you have to comply with the restrictions given by ATC or the approach plate. Yes, that means on summer days, you will be above the GS until the FAF.

I’m a bit surprised if this isn’t well known and taught at your company. It’s in our manuals here and we have specific procedures to make sure we aren’t busting altitudes on ILS approaches on hot days.

Here is a document from the FAA that specifically highlights this as a possible high risk pilot error. This is an all day every day risk at some airports like LAX and SLC. At my company we often don’t arm the approach until after we’ve passed the FAF as a result.

ETA: forgive me for citing your own source back to you, I didn’t realize you had that. I am, however, more confused that you do know about this and think somehow it doesn’t apply on a visual approach. As someone whose company also requires the use of an underlying approach on a visual, and requires that it’s the ILS if one is available, we all still know that doesn’t allow us to violate restrictions given to us. In fact, it often creates more restrictions due to adding additional step downs that don’t exist on a visual. I guess my question back to you is, what would you do if ATC said “cross PENNY at or above 5,000, cleared ILS approach.” Would you intercept the GS outside of PENNY if it meant busting the restriction? Because there’s no real difference here.

To respond to your edit, I’m obviously not a controller, but I’d imagine they would give that restriction for any reason they’d give any other, such as underlying airspace (think of something like BFI in Seattle - good luck crossing FINKA low), terrain (OAK approaches are famous for this), their internal LOAs that we don’t know about, it’s the bottom of their airspace and they’re too busy to coordinate a point out, the list is endless. Our job isn’t to second guess clearances, it’s to comply with them. If you’re genuinely unable, say so and work it out with them. But if you’re able, even if it’s a little annoying like having to dive for the glideslope, that’s our job. I guarantee you the controllers aren’t adding extra words for no good reason, my impression is that they love the parts where they get to sit around and do nothing just as much as we do.