Joseph Stoker was sitting on the couch watching Netflix’s “Big Mistakes” when his partner asked him about one she thought was an obvious blunder: What would he think if a candidate walked into a job interview with an iced coffee?

Stoker, a 40-year-old lawyer in London who works in-house at a tech firm, said he didn’t think the drink would matter. It isn’t evidence of a candidate’s competence or capabilities.