Well that has not been proven - it’s the conclusion of the inquest, yes

I think the McKeague case was pretty much proven to be the dumpster scenario, based on a few factors:

• the weight records on the truck for uplifts: initially were mistaken due to some system error which led to dumpsters not being focussed on initially, but weight record error was later found
• phone movements: McKeague's phone moved synchronously with the dumpster truck along a circuitous route to the dump area from the town centre where he was last seen
• fit of CCTV (in terms of where he was seen/ not seen and the area of centre he never exited from)

However, I'd generally agree with you that such scenarios are bizarrely rare and would still be very unlikely to explain Brian Shaffer's disappearance. If the phone pings for Shaffer's phone in two areas some distance from UTS are correct that would also suggest the dumpster theory is irrelevant in his case.