Penetration through Vinyl Siding (gas lines, etc)

Good day everyone,

I am a new inspector and am currently going through the CPI first year courses.

During the Exterior Inspection Training Video of the How to Inspect the Exterior Course, there are moments when the instructor, Ben, is inspecting the first home and he comes across multiple penetration points in the vinyl siding. He comments about the need to seal the penetration points.

Since the house had vinyl siding, shouldn’t the sealant be behind the vinyl siding between the sheathing and penetration components so the siding can move freely as temperature changes? Wouldn’t it be incorrect to have the sealant between the
vinyl siding and the penetration components? My understanding is that this would prevent the vinyl siding from moving freely.

Here are the moments during the video I noticed.
8:11 - Pipe penetration of vinyl siding not sealed at siding.
9:10 - 9:52 - Multiple penetration points, including vent. Vinyl has sealant where it meets vent which I think would be incorrect. The flashing noted looks like it should be under the upper siding piece and over the lower piece.
10:00 - Receptacle box looks like vinyl could move freely around it.
11:00 - Double vent looks like vinyl could move freely around.
14:18 - Gas line looks like vinyl could move freely around.

What is the correct way for sealant, caulking, and flashing to be installed with vinyl?

Thank you,

Most (good) contractors use duct seal compound:

Home Depot