Some audits do say that phones should not be used except for photos. I am thinking of the revealed audits on GFK specifically say this. They do not want to see shoppers talking on the phone during an audit as that is unprofessional.
Also, talking or obviously texting on a phone during a regular mystery shop gives the salesperson an excuse for not greeting you right away, etc. as they did not want to bother you while you were in the middle of a phone conversation.
Shopping across Indiana but mostly around Indianapolis.