Originally Posted by
entflight
In your above cases, the cabin crew definitely should already know the status of the passenger, Diamond, Gold, etc. beforehand and might even have greeted the passenger accordingly during boarding. And if you subsequently use apps to switch FFP or un-identify your CX status, will the cabin crew then treat you as if you are nobody?
It really depends: As far as I understand the crew (or the IFM) can refresh the manifest on the tablet whilst on ground, although most do not once boarding has commenced unless there are last-minute changes (or they're just a little slow in getting things up and running).
So in my too-many times changing from BA Gold (OWE) to QF (previously zero status) midway whilst boarding, I have had a few times where they do identify me as EM on the system whereas on others I just don't have the EM tag attached to my name on the system, although those are on the rarer side. The most egregious one was probably a BKK service that went out full on the 77P with last minute DM/GO upgrades into J, where they literally did meal option selection from EM/DM/GO all the way down to OWR and nil and the cabin crew doing orders really gave a flying flute about nil status pax and just told them to choose it from his tablet.
Truthfully speaking though EM/DM/GO or not the only times it makes a big difference is the IFM greeting + meal selection, and usually the latter tends to be done before departure.