Eh - asking for FB is easy, u just get into a habbit of it, but those damn greenbags is bullshit - why should we try and guilt people into a lifestyle choice? So i dont ask for them - and i guess mystery shoppers make alot of eye contact, watch what ur doing alot, dont ignore u like some customers (like there responsive when u ask them "Hi how are you?") etc. But thats just general speculation.
Edit: and yeah, being reminded to ask for FB is annoying as hell, do they think we're little kids? and its annoying when the CSM asks us at the start of every fucking shift to watch out for mystery shoppers.